Minify JavaScript

Starting in Tiki18: Make the filenames of minified JavaScript files be based on the contents of all the files, not just the filenames, so that when anything changes within a file, i.e. after an upgrade or bug fix, browsers will automatically get the new version of the code (following clearing the tiki caches only). The CSS part is done in Tiki19

New in the performance admin panel in Tiki4, you can activate to aggregate and compress all javascript files in one. In some tests, this has permitted to generate a 10 point increase when testing with Yahoo! YSlow