Replaced assert with zl_assert to allow us to customize error handling. Also added a function to set the env so the zl_assert macro can use it to return to the pref state. Still need a check for the env pointer!
More enhancements to the assert system revolving around the env pointer, should now resume under iOS 8. Maybe better organization in the future? (creating a separate zl_assert file) but this will do for now.
Merge branch 'feature/zl_assert' of https://github.com/patrickmeehan/moai-dev into develop-pointinside