- Wrapped IO into filesys_interface.

 - Implemented "get_config_value" and "get_config_option_names".

 - Implemented install-dev.

 - Implemented handling of DEV_INSTALL_PREFIX.

 - Adapted to pkg-config.
 - Cleaned up config.*.mk files.

 - Reverted erroneous b3 version number raise.

 - Raised version number due to 8-bit-sound suspending, installation path
   updates, .mk file and Makefile improvements.
 - (Second raise due to forgotten b2 increment.)

 - Raised version number due to 8-bit-sound suspending, installation path
   updates, .mk file and Makefile improvements.

 - Temporarily disabled "force-8bit-sound" flag usage, should be
   re-implemented by sound-interface-specific option parsing.

 - Disabled tracing and gdb symbols by default.

 - Made $(HOME)/opt/fizmo default install prefix as long as we're in beta
   state.

 - Made Makefile aboid a warning when used distclean on an empty build.

 - Cleaned up .mk files.