Fixes for Windows

Two fixes:

1. On Windows, `"` (double quote) and `\` (backslash) are illegal characters for file names, resulting in a failing clone.
2. For some reason, the regex `/\n$/` doesn't properly trim the path of the executable when using binaries in `PATH`, resulting in `ENOENT`errors.

If you don't care about 1. let me know and I'll submit a separate pull request (tests don't compile on Windows anyway). 
The second point would be nice to be fixed, otherwise I'm forced to explicitly point fluent-ffmpeg to all binaries in my project.