Fixes and additions to the source

- Fixed a bug which delayed the last running animation
- Improved efficiency of jCanvas animations
- Fixed a bug which restored the canvas unnecessarily for custom
jCanvas methods
- Added a build script for building and compressing jCanvas
- Added a new date-like version number to jCanvas for developers
Merge branch 'master' of https://github.com/caleb531/jcanvas
DKS - removed explicit jQuery version numbers, now always using the latest from code.jquery.com
DKS - added test file to demonstrate the opacity animation issue with Caleb's recent animation code changes