Adding /regex/ style expression support

This patch adds support for using Javascript's /regex/ style notation for specifying regular expressions. This makes developing regular expressions for languages easier as it is no longer necessary to double escape each \ for Javascript, and it allows supporting IDEs to check the validity of Regular Expressions at design time.

This patch also updates the build script to support these '/' escaped expressions, treating anything between / / the same way a string is usually treated. If you notice any problems with this handling, let me know.