Update Minimap to version 1.2.

- Change some defaults: better colors, reduced update delay.
- `minimap-tag-only': New experimental feature to only display an
  'abstract view' of the buffer with overlays generated from
  Semantic information.  Works only for buffers parsed by Semantic.
- `minimap-highlight-line': Highlight current line in Minimap.
- Fix autoloads.
- Display lines denoting beginning/end of functions in Semantic
  overlays.