allow msvs_version to be passed in via args
allow msvs_version to be specified via env GYP_MSVS_VERSION
ignore msvs 2010 since it isn't compatible
removed undefined comparison
Revert "allow msvs_version to be passed in via args"

This reverts commit 925b15639640c91935303545c434013fcf500981.
fixed version check for windows
resolves error message with apm update / upgrade
Merge pull request #108 from bradgearon/master

resolving errors with apm upgrade on windows