fixed race condition on the main map, added a test, normalized filepaths, handled windows rename issue

[chrhlnd]

The main map had a race condition. Made a minor test file for ya. Made the test pass on windows, which had issues with your rename. Also normalized the paths with the filepath package.

[sdomino]

@chrhlnd, thanks for the pull request. If you could do a couple of things, that would be great:

• Pull the latest master to make sure everything is up to date (there are currently some conflicts)
• Create a branch for your changes so when they are ready to be merged we can squash them
• Integrate your tests into the tests that are currently on master.

Your changes look good, and I'm confident we'll get them merged in, thanks.

[DBarney]

dropping the read lock and acquiring a write lock is a race condition. Inside the write lock you should check to see if the mutex has already been created, to avoid a second mutex being created.

[chrhlnd]

Re-pushed with the check.