Trust but verify 'scutil' to return ComputerName

Apparently, it is possible to set up a Mac such that
`scutil --get ComputerName` hasn't been set.

This change checks if that fails and falls back to the original
mechanism.

Closes #2155
Closes #2183
fix missing add-zsh-hook in pygmalion.zsh-theme

Fix "command not found: add-zsh-hook" since #3053 removes `autoload -U add-zsh-hook`
Symfony2 plugin use first console found
Symfony2 plugin look for files only
Symfony2 plugin autocomplete for app/console and bin/console
Merge pull request #3087 from hacfi/symfony

Symfony2 plugin use first console found
Merge pull request #2743 from docwhat/issue-2155-scutil

Trust but verify 'scutil' to return ComputerName
Merge pull request #3072 from clippit/patch-1

Fix missing add-zsh-hook in pygmalion.zsh-theme
Add 'chris' theme
Update zsh prompt
Add custom dir to repo
Remove Climate aliases
Remove spec alias
Add irc alias for weechat-curses
Remove before and after context on grep alias
Add gap alias, remove grep alias
Add custom scripts to repository
Rename scripts to have correct load order
Remove unnecessary init scripts
Change LSCOLORS to better match Thayer color scheme