core: fixed printing function name in log message

- based on http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html
core: updated dprint api to enable support for debug level per module

- a callback can be registered to return the log level based on module
  name
debugger: option to set debug level per module

- new parameters:
	- mod_hash_size - size of internal hash table to store levels per
	  module (used to compute power of two with it)
	- mod_level_mode - enable/disable per module log level
	- mod_level - specify module log level
modparam("debugger", "mod_hash_size", 5)
modparam("debugger", "mod_level_mode", 1)
modparam("debugger", "mod_level", "core=3");
modparam("debugger", "mod_level", "usrloc=3");
debugger: documented new parameters related to per module log level
Makefile.defs: version set to 4.1.0-dev5