Some minor changes.

* Order threads by date of last received message
* Skip highlighting in vim by adding +nohl
* Removed charset hooks for now
* Beep on new mail
* Other changes for quicker composing
Better keybindings.

Changed keybindings to be more like Vi(m).
Moved colors into main muttrc file.

Removed old file with colors.
Using Muttrc from distro to integrate gpg and more.

Removed my gpg file. Sourcing muttrc from the distro in stead, as this
should provide GPG support and more.