Ensured that .m/.mm/.xib etc are being read only once and their values stored. Without this they are read by each image being checked, which is insanely inefficient and causes the CPU to become severely overloaded.
Added .gitignore.
Cleared the _fileData dictionary after all checks so that the files can be re-read in case of changes.
Merge pull request #13 from guykogus/master

Files being searched for images are only read once. Great work!