Fixing Header file.
Clean up Demo Code in man pages and lbuxton-simp_test.c

removed #include <stdlib.h> from lbuxton-simp_test.c
removed #include <stdlib.h> and #include "buxton.h" from man page
	code examples
Removed more unneeded functions in lbuxton-simp.c

Also removed them from the header file. Added more comments for functions
that were kept.
Removed buxtond_create_group. Removed buxtond_key_free.
Added more comments to cg_cb, and buxtond_group_create in buxton-simp.h
Added Man Pages for buxtond_set_group and buxtond_remove_group

Edited makefile also to include these man pages.