compositor.f90 refactoring

[smirik]

1. Rename compositor -> composer.
2. Parsing of command line argument should be moved into a function. Better — into a module. E.g. console module.
3. Initialising should be also moved into a function, but inside composer.f90.
4. Parsing of list or range arguments should be moved into a console module.
5. Getting information, clearing e.t.c. should be moved into a separated function. The main function should only invoke some other functions with arguments. It should be small & accurate.