make_distrib improvements:
- Windows: Change the directory and build structure to match other platforms.
- Windows: Create archives of both Debug and Release symbols.
- Windows: Create a separate archive for documentation.
- Add a new "client" mode flag that creates a distribution of cefclient.
- Add "no-docs" and "no-archive" flags.
- Break README.txt files into separate components that can be shared between platforms and distribution modes.

git-svn-id: http://chromiumembedded.googlecode.com/svn/trunk/cef1@1217 5089003a-bbd8-11dd-ad1f-f1f9622dbc98