Rearrange <f> key bindings.

Try using `<fx> m` as a prefix for magit commands.
Set up guide-key.
Use new remember-notes buffer.

Trying this out for org notes that are temporary.
Tweak key bindings.
Add defun to colorize region with ANSI sequences
Add my-unset-key defun.
Tweak projectile keys.

 - add magit support to commander.
 - add command to show ibuffer restricted to project
Make clear-log a bit safer.

Only truncate *.log files.

TBD: Could change this to prompt (rather than fail) for other file extensions.
More key binding changes.

- Use <f9> as prefix for project commands. (projectile)
- Use projectile-commander as action for switching projects