Inflate and deflate leak memory

Here are some added tests that can be used to reproduce the leak: http://github.com/saikat/node-compress/commit/3e0bcdbf71c84dbfb12a1719e2ad450a05d1bafb .  It also has some fixes to the other tests to remove deprecated Node API calls.

Here is a proposed fix for the memory leaks: http://github.com/saikat/node-compress/commit/33ccd392c94f9b86dd6724234958578a81902c4b
