Adding many features

Added `cwd`, `cd`, `stat`, `statDir`, `recursiveStatDir`, `revert`, `submit`, `sync`, `syncDir`, `recursiveSyncDir`, `have`, and `login`.
Added parsing of `p4 fstat` output to JSON object.
Added `path.resolve` to all paths given. Works with relative and absolute paths.
Modify `exec` call to include `cwd` and arbitrary environment vars.