Remove nil specs and pods from installer rep maps
Don't install library without target definition
Keep shell script phase simple and static

The copy resources shell script phase was previously updated every 
time the pods were changed.  This moves the updates to the integration 
library copy resources script and restores the original static single 
line from before the per pod library code.
Only integrate with targets that require it

This restores and merges the original code for determining if a 
user target requires integration.
Bug fixes and cleanup
Update test specs

Many changes are simple API changes, generally centered around the 
renaming of Library to Target.

There are also a lot of additional stubbed or test classes added to 
accommodate for the fact that real Pods installations always have one 
or more integration libraries each with one or more per spec 
libraries.