Simple rewrite of generate-bindings.pl in Python

Closed; superseded by full rewrite in:
Issue 18190004: Add Python flow to bindings generation, move dummy-generating IDL files over
https://codereview.chromium.org/18190004/

Simple rewrite of generate-bindings.pl in Python

This is a simplied version of full rewrite, which is mostly stubs,
with the only substantial logic being reading and processing the JSON.
Imported JSON is then dumped to stdout for inspection.

Includes a test JSON file so not blocked on Perl JSON export patches.
Test via:
./generate_bindings.py --output-directory=test test/BarProp.json

Test data generated by:
md test && ./generate-bindings.pl --outputDir=test --dump-json ../../../Source/core/page/BarProp.idl
...after applying:
Issue 16296004: JSON export from generate-bindings.pl
https://codereview.chromium.org/16296004/


Simplification of:
Issue 15959019: Rewrite generate-bindings.pl in Python
https://codereview.chromium.org/15959019/

BUG=239771

[Nils Barth (inactive), 2013-06-04 04:12:14]

Hi haraken,
Here's the simplified rewrite, mostly just stubs;
only real logic is reading in and processing JSON.