Remove namespace headers from repository

+Namespace.h header files are generated upon project build and thus should not be in the git repo. Otherwise they can dirty the git folder upon small changes to the project file, which gives unnecessary hassle when having nimbus as a submodule.

In the pull request the namespace header files are removed from the git repository, but not from the project. They are added to gitignore. The generation script is moved before the copy headers section in each target's build phase.