revert test module name regex change

reverts code and relevant readme change from commit 
61695fe06eefaea5315076adcb66fdda9afcd18e. For that commit to work, 
the 'mojito-test' module would deed to be special-cased, or the
test selection logic would need to be cleaned up (i.e. select tests
using either a pathname convention, or a yui module name convention,
but not both).