Merge pull request #57 from richardsheridan/master

Fix MSVC build problems
adjust imports on polymer models so that old versions of scipy don't cause bumps to fail entirely
remove openmp compilation option
fix erfc for mac that was broken by windows patch
fix tests to reflect updated doc/examples directories
Retry reflcalc.h MSVC fix.

Maybe this will be more portable.
New sld method

Adding the slabs argument allows universal application of an sld method
to any mixture of materials. Caching the result avoids duplicate
computation since the profile function is expensive.

This modification was pervasive. Is there a way to get Pz, Pw globally
without calling slabs.microslabs(thickness)?
Merge remote-tracking branch 'origin/idea-sld-method' into idea-sld-method

Conflicts:
	refl1d/polymer.py