[Ur] New release

[Adam Chlipala]

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

CHANGELOG for this release:

- New support for CSS style code embedded in Ur/Web programs.
   Two recommended usage methods:
   1. Use 'style' attributes with normal CSS syntax inside string literals.
   2. Generate styles programmatically with the Style module of the Gui 
library
      (distributed separately).
- 'dynStyle' attribute, which is to 'style' as 'dynClass' is to 'class'
- Parsing of standard syntax for 'class' attributes, via specially 
interpreted
   string literals
- New optional suffix for 'rewrite' in .urp files: [-]
- Compiler error message improvements, including simplification of types
- New command line parameters: '-boot', '-dumpTypesOnError', '-unifyMore'
- New .urp directives: 'linker'
- Support for speeding up compilation by caching type inference results:
   Run 'urweb daemon start' to spawn a background process,
   'urweb daemon stop' to kill it.
- Enforcement of uniqueness of top-level module names across a project
- Adjust error message format to match Emacs compilation mode defaults
- More HTML attributes added
- New antiquote syntax for 'PRIMARY KEY'
- Bug fixes and improvements to type inference and platform compatibility