Revert "libbuxton: Add poll method"

This reverts commit 6af4366ded33a2f9b1beb809f3273f6efee3119e.

This was put in as a stop gap for developing the gtk client and can be removed
now.

Conflicts:
	src/include/buxton.h
	src/libbuxton/lbuxton.c
	src/libbuxton/lbuxton.sym