Fixing podspec

The pod spec downloaded everything except the AMSlideMenu/AMSlideMenu folder, and it gave an error about not being able to run the command StripStoryboard on the compiled storyboard file (.storyboardc).

I have no idea what any of that means, but I looked at another pod spec and tried to emulate what they had done, and at least it compiles now and the actual source files are there, I haven't tested if it works or not yet, I'll be doing that in a moment.