Initial commit
A bit of refactoring, plus a bug fix.

See the comment re: </>
Remove redundant do
Various cleanups.

Thanks to ski on #haskell for the suggestions.
Use stripPrefix.

The prefix should never be anything other than src; this makes dropRoot
fail loudly if it is. Thanks again to ski for the suggestion.
Rename dropRoot -> stripSrc.

I feel this is slightly more descriptive of the actual semantics.
Rename getFileTreeStatus -> lStatTree.

getFileTreeStatus looks like an extension of getFileStatus, but it's
actually more like getSymbolicLinkStatus. getSymbolicLinkStatus is just
too long, but let's give it a name that more accurately hints at it's
semantics.

The prior name isn't coincidental -- when it was named, it *was* an
extension of getFileStatus, but that turned out to be not what we want.
Cabalize, add license.