[Fix #477] Add instructions for updating Prezto
[Fix #479] Start only one ssh-agent instance
Support command-not-found on Arch Linux

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Add Ocaml module

Manage local Ocaml modules with OPAM.

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Add and update module descriptions
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Add and update module descriptions
  Add Ocaml module
  Support command-not-found on Arch Linux
  [Fix #479] Start only one ssh-agent instance
  [Fix #477] Add instructions for updating Prezto