Add php53-apcu
Add php53-apcu

Seems there is no reason this formula cannot be provided for php54-apcu

Install inforations says PHP should be >= 5.1.x
https://github.com/krakjoe/apcu/blob/master/INSTALL#L4-L7

TomK/homebrew-php,mkalkbrenner/homebrew-php,ablyler/homebrew-php,dguyon/homebrew-php,philcook/homebrew-php