rename MediaCore's 'jwplayer.js' to 'jwplayer_.js'.

JW Player 6 scans all script tags to check for a referenced 'jwplayer.js' file and will just take the first one to load other resources (jwplayer.flash.swf, jwplayer.html5.js).

Without this change JW Player 6+ won't start in JS debug mode ('?debug=True') mode.
extract fake request building into a plain function so it can be used also outside of tests (most notably when building the Sphinx docs)
move common environment/request setup functionality into mediacore.lib.test.support
fake requests should also set up a basic translator
export 'StorageURI' from mediacore.lib.storage so we have a unified API and all storage-related class are available from that module
use test support functionality to set up a dummy Pylons environment/request to build the documentation.

This also removes the necessity of editing the SQLAlchemy url in development.ini just to build the docs without DB interaction.
update InterSphinx URLs
store real JW Player instance reference (which is returned from 'setup()') to prepare moving to JW Player 6 later on
recompile JS
move link to media to email body when the 'share by email' feature is used
add workaround in pylons.translator setup for unit tests (sometimes pylons.translator is not a StackedObjectProxy)
add Group.example method to provide simple test fixtures
redirect only admins and editors to the admin area after login (common users will be redirected to the front page)
fix bug which prevented a MediaCore admin to add new RTMP urls

Thanks to Rubén for reporting the issue.
fix Python 2.4 support in uri validator when adding new media file
disably login link above nav bar on all public pages
add appearance setting to display login link on public pages
add link to admin section in login bar if user has appropriate permissions
disable Google Video storage engine for new installs as Google Video was shutdown last year
deprecate Cooliris and do not enable it for new installs.

If someone is interested in maintaining the Cooliris integration, I'm happy to enable it again for new installations.