DEV: added even='avg' key to np.simps() to address odd interval count
DEV: added even='avg' key to np.simps() to address odd interval count

Adding this key ensures that integration will proceed regardless
of whether interval count is even or odd.
If speed becomes an issue the 'even' key can be set to 'first' or
'last' since currently integration is completed twice and is averaged.

licode/scikit-xray,danielballan/scikit-xray,CJ-Wright/scikit-beam,CJ-Wright/scikit-beam,scikit-xray/scikit-xray,tacaswell/scikit-beam,ericdill/scikit-xray,giltis/scikit-xray,tacaswell/scikit-xray,licode/scikit-xray,giltis/scikit-xray,danielballan/scikit-xray,yugangzhang/scikit-beam,danielballan/scikit-xray,yugangzhang/scikit-beam,celiafish/scikit-xray,tacaswell/scikit-beam,hainm/scikit-xray,tacaswell/scikit-xray,giltis/scikit-xray,licode/scikit-beam,tacaswell/scikit-beam,celiafish/scikit-xray,CJ-Wright/scikit-beam,licode/scikit-xray,celiafish/scikit-xray,ericdill/scikit-xray,Nikea/scikit-xray,Nikea/scikit-xray,tacaswell/scikit-xray,yugangzhang/scikit-beam,Nikea/scikit-xray,hainm/scikit-xray,hainm/scikit-xray,licode/scikit-beam,ericdill/scikit-xray,scikit-xray/scikit-xray,scikit-xray/scikit-xray,licode/scikit-beam