Better support for ** in paths with :Vsunittests

Say you have created a new file and you want to create unit tests for it
in the appropriate location, but your source and unit test directory
paths have ** in them. This commit should allow you still to be able to
do that.

For example, if you created src/modules/main/mine.js, and your source
directory path is src/modules/**, and you have you want to create a unit
test at src/tests/main/mine.spec.js, and your unit test directory path
is src/tests/**, Vsunittests should now be able to figure this out.