Cleaning up some of the simpler warnings cluttering the Issue Navigator.

Now that we're building for 64-bit, we have to cast all of our NSIntegers and NSUIntegers before using them in format strings.
Clean up the last of the format string cast warnings.
Clean up implicit conversion warnings.
Remove unused launch image to quiet warning.
Merge pull request #543 from MIT-Mobile/3.6/easy-warnings

Clean up most of the trivial warnings