resolves #1223: fix interaction with symbolic links

- symbolic links are followed if they are not broken
- move `lookupFiles()` into `utils` module
- add some tests for the symbolic link stuff
- build
Merge branch 'mocha-1223'
Fixes test for utils.lookupFiles.

Returned list of files is in unspecified order, as it uses the underlying
fs calls to retrieve them, which also return them in unspecified order.
Adds semicolon missing from pull-request.