Diminish my-keys mode.
Remove key bindings for non-default packages.

Reorganizing el-get extensions, think it makes more sense to keep
optional extension key bindings defined where the extension is added.
Add names for some custom features, for use with eval-after-load etc.

Also remove wgrep setup, that should go where we load wgrep.
Rename ack to my/ack to avoid possible collision.

Not really using this, need to revisit various ack wrappers.
Clean up loading of other init files.

 - Remove reference to deleted my-mode-line.el.
 - Load my-keys early so that other init files can use it.