Normalize the Xcode project tree.

The INAppStoreWindow library is now at the root level.
Move Extensions into the INAppStoreWindow library folder.
Organize the file hierarchy in a more manageable and logical fashsion.
Remove user-specific file that does not belong in Git.
Fix project name in workspace.
Merge pull request #166 from petroules/organization

Organize file hierarchy and Xcode project tree into something more manageable and logical.