podspec fixed: ** to reference subfolders, non existent 'AnotherFramewor...

I was not able to used MBCalendarkit, due to some bugs in podspec file:

- it references only the files at folder MBCalendarKit/CalendarKit, and not the files inside subfolders
- it also lists 'AnotherFramework' in podspec, and that framework doesn't exist.

I fixed these bugs and could use CalendarKit in my project. Thanks!