fixes bug in returned instance of gulp-foxy-less() - it has to be a function to create a new through2-stream instead of reusing
changes the readOnInit option to read the .less files asynchronous
updates dependency for globbing from glob to glob-all to support arrays of globs... globs.... globs... globs
updates README due to new glob-all support
refactors plain function definitions into FoxyLess constructor function to support distinct functions on such instance:

.preAnalyze() // to have 'readOnInit' more explicit - instead having it as part of options
.transform() // to create the through2 transform stream