v2.0.6 — push to a remote from the dashboard, never forced

Added

• Push to a remote on the dashboard: every remote with its address (credentials
  left out) and how the checked out branch stands against it (up to date, to push,
  behind, not there yet); Fetch, and Push of a chosen local branch to the branch of
  the same name. Never forced; asks first with branch, remote and ahead/behind; only
  known remotes and branches; git never waits for a password (no prompt, ssh batch
  mode, 90 second limit), so a missing credential shows as git's error.
• A git_manager/push policy function: pushing needs it; the dashboard and Fetch
  need git_manager as before. Roles with every function of the module have it.

Updated

• The backup page loads no external files (jQuery UI and its theme came over
  http from Google, and were not used).