exec-729514: Add prefix to requisition

With a prefix then we will first lookup what was typed with the given
prefix, before trying the unprefixed version.

The eventual goal is to make the following be equivalent (using git as
an example command)
>> git add -a
>> git commit -m blah
Or
>> context git
>> add -a
>> commit -m blah

Signed-off-by: Joe Walker <jwalker@mozilla.com>
exec-729514: Hack to allow access to Requisition

We want users to stay away from Requisition, but the context command is
going to need to manipulate it, so we allow access to the Requisition
from a context in as nasty a way as possible to dissuade general use.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
exec-729514: Add a 'context' command

This allows us to add a magic prefix to commands. See notes in previous
commit.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
exec-729514: Refactor - unindent 'intro' command

Signed-off-by: Joe Walker <jwalker@mozilla.com>
exec-729514: Outstanding work: WARNING WILL REBASE

This branch will be rebased before it is done. You have been warned.