Optimised writeFileBytes function.
Now ignoring OSX meta files (@DavyLandman)
db273f52f5cd884487ccfbd4e1c2b39bd82d11da forgot to update composeJavaM3

Thanks @SanderBenschop for reporting
Fixed 'yield' semantics.
Merge branches 'gll-experiment' and 'master' of https://github.com/cwi-swat/rascal into gll-experiment