[Ur] New release

[Adam Chlipala]

Available as usual at: http://www.impredicative.com/ur/

CHANGELOG for this release:

- Treat local variables the same as module-level variables, for the 
purpose of
   implicit argument insertion
- New 'noXsrfProtection' directive for .urp files
- Non-debug builds omit source location information in error messages 
shown to
   the user (but keep that information in log entries)
- Basis.getHeader and Basis.setHeader
- Basis.show_css_class
- Basis.currentUrlHasQueryString
- Make Basis.rand cryptographically secure
- Client-side versions of Basis.now and Basis.show_time
- Bug fixes
- Improvements to auto-configuration and build process (now builds with 
LLVM's
   Clang!)
- Clarifications in the manual