Explicit cast to long and updated gitignore file

This PR includes 2 changes:

1. Adds explicit cast to long instead of using `NSInteger` for the `fileHash` string.
![wrist_presenter__mhwdirectorywatcher_m](https://cloud.githubusercontent.com/assets/251031/3866577/85557f86-1fd8-11e4-8297-e88af0f7a996.png)

2. Uses an improved `.gitignore` file so files like `xcshareddata` are not accidentally checked in on future PR.