Prepare for 0.7.1 release. (#688)

Summary: Pull Request resolved: #688

Test Plan: `pod lib lint` passes

Reviewed By: richardjrossiii

Differential Revision: D61995551

Pulled By: nlutsenko

fbshipit-source-id: 9cb88c8e8b6afb1ebbfd0821e7f426ffe45998e0

Update podspect version to 0.7.0.

Fix Basic Authorization header

Guard potential unavailability of NSStreamNetworkServiceTypeCallSigna…

…ling.

Bump pod version to 0.5.1

Bump pod version to 0.5.0

Merge pull request #290 from mogstad/carthage

Add dynamic framework for iOS

Bump pod version to 0.4.1

Merge pull request #253 from square/dimitris/version

Update version number to 0.4

Updating podspec