Fix unit tests

`path.join` is a varargs function and joins all arguments. The `map` call passes
index and full array as further arguments.

Test Plan:
all jasmine tests pass
add travis status image to readme
Merge pull request #4 from kassens/testfix

Fix unit tests
Add a main.js file so that require("node-haste") will work.

Other modules in lib/ should probably be exported, but I chose to be
conservative about what we export for now.
Merge pull request #5 from benjamn/add-main.js-file

Add a main.js file so that require("node-haste") will work