Added cfuncs cython file to replace weave code.
Added cfuncs cython file to replace weave code.

landlab/landlab,csherwood-usgs/landlab,laijingtao/landlab,SiccarPoint/landlab,amandersillinois/landlab,landlab/landlab,laijingtao/landlab,cmshobe/landlab,csherwood-usgs/landlab,ManuSchmi88/landlab,landlab/landlab,RondaStrauch/landlab,decvalts/landlab,RondaStrauch/landlab,cmshobe/landlab,Carralex/landlab,amandersillinois/landlab,RondaStrauch/landlab,Carralex/landlab,cmshobe/landlab,Carralex/landlab,SiccarPoint/landlab,ManuSchmi88/landlab,ManuSchmi88/landlab,decvalts/landlab