Documentation

• More improvements and fixes to the User Guide. (Ian Clatworthy)
• Add information on cherrypicking/rebasing to the User Guide. (Ian Clatworthy)
• Improve bug tracker integration documentation. (Ian Clatworthy)
• Minor edits to Bazaar in five minutes from David Roberts and to the rebasing section of the User Guide from Aaron Bentley. (Ian Clatworthy)