Added missing newlines to EOF in several files.

In our project we have, among other best-practice settings, GCC_WARN_ABOUT_MISSING_NEWLINE = YES in order to ensure sane line endings in our source files. Several of zipzap's headers and sources do not end with a newline, which breaks our build on such `#import`s.  It would be wonderful if zipzap would terminate all source with newlines.

There should be no side effects to doing so.