Fix performance regression
Use `is`
Merge pull request #3234 from mdboom/unit/fix-performance-regression

Fix performance regression getting format class for Unit
Add initial install and appveyor config.
Disable 3.4+numpy1.7.1 and also allow builds to fail.

Changes behviour so if one build fails the whole matrix is not terminated.
reallow fast fail and use AppVeyor platform for arch.

Disabling fast fail broke the world.
only build 2.7 and 2.6.
Rename anaconda install script.
Whitespace fixes
Set PYTHON_ARCH for 64 bit

Conflicts:
	appveyor.yml
Add missing windows configuration script
Temporarily disable failing tests on Windows
Temporarily skip more failing ascii table io tests on Windows
Add missing import
Skip failing doctest  on windows
Combine conda installs to make sure correct numpy version is used
Add jinja2 to conda dependencies
Skip more failing tests on appveyor
Skip tests using APPVEYOR env variable.
Reduce appveyor matrix to python 2.6 and 2.7 with numpy 1.9.1