ENH: configure function on fly

[CJ-Wright]

Currently you must load up the data_reduction module to access glbl configured functions. It might be nice to configure functions on the fly, allowing you to mix and match the configured functions (this would also help if you change the glbls and need to re-configure functions to the new glbls).

from glbl_manager import config_func
from glbl import glbl
f = func
cf = config_func(f, glbl)