Remove debug messages from CMakeLists.txt
Install emerald.py next to libpyemerald.so and load it from there

- add install rules to install libpyemerald.so in global or user-specific
  emerald engine directory, and emerald.py in a pyEmerald subdirectory next
  to the lib
- make our C code load the emerald.py file from pyEmerald subdirectory in
  user-specific or global emerald engine directory
- add autogeneration of config.h to pass some paths as preprocessor
  macros
Change the settings key of our engine to "pyemerald_settings"
Add IDE files to .gitignore (cmake can generate these)