Updates podfile to use latest DTCoreText and WPiOS shared.
Updates Podfile to latest DTCoreText and WordPress-iOS-Shared

WordPress-iOS-Shared was changed to point to github vs the pod until the pod can be updated.
Merge pull request #1896 from wordpress-mobile/issues/update-dtcoretext-pod

Update DTCoreText pod
Merge remote-tracking branch 'origin/develop' into issue/1870-implement-simperium-sync

Conflicts:
	Podfile.lock
	Pods/MGImageUtilities/MGImageUtilities.podspec
	Pods/Manifest.lock
	Pods/Pods.xcodeproj/project.pbxproj