[Fix #477] Add instructions for updating Prezto
[Fix #479] Start only one ssh-agent instance
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  [Fix #479] Start only one ssh-agent instance
  [Fix #477] Add instructions for updating Prezto
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
Bump minimum supported Zsh to v4.3.11
Don't override customized environments in subshells

Only set up environment for the top-level shell, and allow it to be
inherited normally.

A top level shell is usually a login shell, but can also be a
non-interactive, non-login shell in certain cases, such as when
executing an SSH remote command.

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Add Rails 4 bin path
Rewrite _rails-command to work from app subdirectories
Do not specify a bundler install path
Git ignore bundler vendor/assets
Comment a typeset
[Fix #362, Fix #384] Set Mac OS X 10.6 terminal window title
Remove unused GNU Screen window number format
Rewrite terminal auto-title
Simplify auto-titling
Prefix internal functions
Unsufix internal functions
[Fix #324] Add configurable terminal window and tab title formats