Replace MTCA4U with ChimeraTK and avoid filename collisions

[smarsching]

MTCA4U has been renamed to ChimeraTK, but our source code still uses "MTCA4U" in many places. All these references to "MTCA4U" should be replaced with "ChimeraTK".

In particular, the namespace mtca4u should be changed to chimeraTK. In fact, as ChimeraTK contains many components now, we should consider using chimeraTK::controlSystemAdapter.

As this change will require changes in all code using the control-system adapter, we should also include another change that seems reasonable, but will also break existing code: We should put the header files in a directory, so that their filenames do not collide with the headers from other libraries. I suggest moving them to chimeraTK/controlSystemAdapter. As this will have the result of making the reference that has to be specified in #include directives awfully long, we should create a meta header-file chimeraTK/controlSystemAdapter.hpp that includes all other headers. Basically, this is the strategy that is also used by the Boost library.

Last but not least, we should rename the binary library from libControlSystemAdapter to libChimeraTKControlSystemAdapter, so that we do not collide with another "ControlSystemAdapter" library.

[smarsching]

As just discussed with Martin Hierholzer and Martin Killenberg, all code should go into a single namespace called ChimeraTK (with a capital C). The path for the header files should be ChimeraTK/ControlSystemAdapter. The built library should be called ChimeraTK-ControlSystemAdapter (so libChimeraTK-ControlSystemAdapter.so on Linux).

[smarsching]

The changes have been implemented as outlined in the last comment and have been merged into the master branch.