Add support for ClearCase snapshot views.
Add support for ClearCase snapshot views.

This is especially useful for Windows installations due to the pathname
limitation.

Tested on Windows ReviewBoard 1.6.11 installation.
Did some basic tests on Linux.

Reviewed at http://reviews.reviewboard.org/r/3322/

1tush/reviewboard,chipx86/reviewboard,1tush/reviewboard,1tush/reviewboard,sgallagher/reviewboard,bkochendorfer/reviewboard,reviewboard/reviewboard,sgallagher/reviewboard,KnowNo/reviewboard,custode/reviewboard,sgallagher/reviewboard,beol/reviewboard,sgallagher/reviewboard,brennie/reviewboard,brennie/reviewboard,1tush/reviewboard,KnowNo/reviewboard,davidt/reviewboard,brennie/reviewboard,davidt/reviewboard,chipx86/reviewboard,KnowNo/reviewboard,1tush/reviewboard,reviewboard/reviewboard,1tush/reviewboard,bkochendorfer/reviewboard,custode/reviewboard,1tush/reviewboard,bkochendorfer/reviewboard,1tush/reviewboard,custode/reviewboard,davidt/reviewboard,1tush/reviewboard,reviewboard/reviewboard,KnowNo/reviewboard,davidt/reviewboard,reviewboard/reviewboard,beol/reviewboard,chipx86/reviewboard,beol/reviewboard,beol/reviewboard,chipx86/reviewboard,bkochendorfer/reviewboard,custode/reviewboard,brennie/reviewboard