[Ur] New release

[Adam Chlipala]

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

CHANGELOG for this release:

- Improvements to type inference and error messages
- New 'dynClass' pseudo-attribute for most HTML tags
- New 't.*' notation for selecting all columns of a table
- New SQL functions: 'lower' and 'upper'
- 'timeFormat' .urp directive
- Client-side 'debug' and 'naughtyDebug' calls use a browser debug 
console, if available
- Allow 'source' values to be returned by RPCs
- Change the HTML context classification scheme in 'Basis'
- Rename 'Top.id' to 'ident' to avoid clash with 'Basis.id'
- More client-side function implementations
- Some expanded reference manual sections
- Tweak to linker command line argument order (to prevent issues with 
new Ubuntu versions)
- Bug fixes