PKG: MSVC build fixes by Christoph Gohlke.
Use log(2) instead of log10(2)
Use log(2) instead of log10(2)
Merge remote-tracking branch 'cgohlke/patch-2' into msvc_build_fix

Conflicts:
	skimage/filter/rank/_crank16.pyx
	skimage/filter/rank/_crank8.pyx