Fix licensing headers and move most third party code to third_party/...

README.git-cl.codereview

-The git-cl README describes the git-cl command set.  This document
-describes how code review and git work together in general, intended
-for people familiar with git but unfamiliar with the code review
-process supported by Rietveld.
-
-== Concepts and terms
-A Rietveld review is for discussion of a single change or patch.  You
-upload a proposed change, the reviewer comments on your change, and
-then you can upload a revised version of your change.  Rietveld stores
-the history of uploaded patches as well as the comments, and can
-compute diffs in between these patches.  The history of a patch is
-very much like a small branch in git, but since Rietveld is
-VCS-agnostic the concepts don't map perfectly.  The identifier for a
-single review+patches+comments in Rietveld is called an "issue".
-
-Rietveld provides a basic uploader that understands git.  This program
-is used by git-cl, and is included in the git-cl repo as upload.py.
-
-== Basic interaction with git
-The fundamental problem you encounter when you try to mix git and code
-review is that with git it's nice to commit code locally, while during
-a code review you're often requested to change something about your
-code.  There are a few different ways you can handle this workflow
-with git:
-
-1) Rewriting a single commit.  Say the origin commit is O, and you
-   commit your initial work in a commit A, making your history like
-   O--A.  After review comments, you commit --amend, effectively
-   erasing A and making a new commit A', so history is now O--A'.
-   (Equivalently, you can use git reset --soft or git rebase -i.)
-
-2) Writing follow-up commits.  Initial work is again in A, and after
-   review comments, you write a new commit B so your history looks
-   like O--A--B.  When you upload the revised patch, you upload the
-   diff of O..B, not A..B; you always upload the full diff of what
-   you're proposing to change.
-
-The Rietveld patch uploader just takes arguments to "git diff", so
-either of the above workflows work fine.  If all you want to do is
-upload a patch, you can use the upload.py provided by Rietveld with
-arguments like this:
-
-  upload.py --server server.com <args to "git diff">
-
-The first time you upload, it creates a new issue; for follow-ups on
-the same issue, you need to provide the issue number:
-
-  upload.py --server server.com --issue 1234 <args to "git diff">
-
-== git-cl to the rescue
-git-cl simplifies the above in the following ways:
-
-1) "git cl config" puts a persistent --server setting in your .git/config.
-
-2) The first time you upload an issue, the issue number is associated with
-   the current *branch*.  If you upload again, it will upload on the same
-   issue.  (Note that this association is tied to a branch, not a commit,
-   which means you need a separate branch per review.)
-
-3) If your branch is "tracking" (in the "git checkout --track" sense)
-   another one (like origin/master), calls to "git cl upload" will
-   diff against that branch by default.  (You can still pass arguments
-   to "git diff" on the command line, if necessary.)
-
-In the common case, this means that calling simply "git cl upload"
-will always upload the correct diff to the correct place.
-
-== Patch series
-The above is all you need to know for working on a single patch.
-
-Things get much more complicated when you have a series of commits
-that you want to get reviewed.  Say your history looks like
-O--A--B--C.  If you want to upload that as a single review, everything
-works just as above.
-
-But what if you upload each of A, B, and C as separate reviews?
-What if you then need to change A?
-
-1) One option is rewriting history: write a new commit A', then use
-   git rebase -i to insert that diff in as O--A--A'--B--C as well as
-   squash it.  This is sometimes not possible if B and C have touched
-   some lines affected by A'.
- 
-2) Another option, and the one espoused by software like topgit, is for
-   you to have separate branches for A, B, and C, and after writing A'
-   you merge it into each of those branches.  (topgit automates this
-   merging process.)  This is also what is recommended by git-cl, which
-   likes having different branch identifiers to hang the issue number
-   off of.  Your history ends up looking like:
-
-       O---A---B---C
-            \   \   \
-             A'--B'--C'
-
-   Which is ugly, but it accurately tracks the real history of your work, can
-   be thrown away at the end by committing A+A' as a single "squash" commit.
-
-In practice, this comes up pretty rarely.  Suggestions for better workflows
-are welcome.