Add tool man pages in asciidoc format

Add tool man pages in asciidoc format.

nroff mandoc-format man pages can be generated by running:

a2x --format manpage \
    --attribute 'mansource=Crashpad' \
    --attribute 'manversion=0.6.0' \
    --attribute 'manmanual=Crashpad Manual' \
    --attribute 'revdate=October 2014' \
    manpage.ad

For HTML output, use --format xhtml.

R=rsesek@chromium.org

Committed: https://chromium.googlesource.com/crashpad/crashpad/+/f59e3e6b780100a705dd583f44467f7c1f9b14bd

[Mark Mentovai, 2014-10-16 22:07:54]

mark@chromium.org changed reviewers:
+ rsesek@chromium.org

[Robert Sesek, 2014-10-16 23:05:09]

LGTM. If GYP had a concept of runnable targets, this would be a good candidate
for one.

[Mark Mentovai, 2014-10-17 12:51:35]

Patchset #2 (id:20001) has been deleted

[Mark Mentovai, 2014-10-17 12:52:33]

Made a minor update to the format used for section headers, and renamed .txt to
.ad to make them easier to find and identify.

[Mark Mentovai, 2014-10-17 15:01:59]

Committed patchset #3 (id:60001) manually as
f59e3e6b780100a705dd583f44467f7c1f9b14bd (presubmit successful).