v0.8.1

• switch branches with conflicts
• auto stash on merge if necessary
• upgrade to pygit2 v0.23
• some small changes:
  • sh/set-head flag for gl branch
  • v/verbose flag for gl branch to additionally output the head of each branch
  • b/branch flag for gl history to tell which branch to show history from
  • l/limit flag for gl history to limit the number of commits to show
  • c/compact flag for gl history to output history in a compact format
  • honor core.pager
• bug fixes