Make background for branch name transparent

[SlyNet]

Currently branch name has background that is different from settings you choose for powershell

[JeremySkinner]

The default behaviour is to make the branch background the same as the background for powershell. You can change this to whatever you like by setting $global.PoshHgSettings.BranchBackgroundColor

The default is set to $Host.UI.RawUI.BackgroundColor - make sure you haven't changed this to something else in your profile.