allow disabling of modules in config file via "use_module_xyz false"

this allows optional lines like
  use_module_laser    false      # disable module
  use_module_player  true       # enable module
default is true.
Macros FORCE_MODULE (unconditionally) and USE_MODULE (via config) are used to ease module creation in main().

As an example I added all module lines to the delta config.

--HG--
extra : source : 15fd47f94b8ec7b5b927cb11210707cf012f3657