Aggressively re-factor. Add many improvements.

+ Adds meeting decline button.
+ Shows more meeting context (attendees, one-line description).
+ Settings have been moved out into a separate activity accessible via
the standard Android app menu.
+ Refresh button added to app menu.
+ Actions now grouped into travel and alternative.
+ Map enlarged in terms of height and breadth to be more useful.
+ Update manifest to include a missing required permission (would cause
app crash on new device install).