BUG: DVCSError Invalid signature on Windows platform

Bug: Unable to create snippet submissions (create a repo) on Windows
platform
Exception raised: DVCSError;
Exception value: DVCS Command Failed 255: Invalid Signature
ENH: add clickjacking middleware
Merge pull request #147 from ksurya/clickjack

ENH: add clickjacking middleware
Merge pull request #142 from ksurya/windows-bug

BUG: DVCSError Invalid signature on Windows platform