Add 32-bit windows build to appveyor
Add build status badges to the readme
Workaround a bug in MSVC 2013 x86 32-bit

It appears MSVC doesn't respect its #pragma fenv_access(on)
option, and reorders floating point operations across
tests of the floating point status flag.

TODO: Need to report this bug to MS.
Merge pull request #178 from mwiebe/appveyor

Add 32-bit windows build to appveyor