Merge pull request #2 from daid/SteamEngine

Update Cura from daid/Cura
Bugfix TweakAtZ: check for old flow rate added, version updated to 3.1.1
Merge pull request #742 from Dim3nsioneer/SteamEngine

Bugfix TweakAtZ: check for flow rate
RC4
Merge branch 'SteamEngine' of github.com:daid/Cura into SteamEngine
Fix for if Cocoa library is not found.
Merge branch 'SteamEngine' into PinkUnicorn