[#52] Add zstyles to configure syntax-highlighting
[Fix #52] Add zstyles to configure history-substring-search
[Fix #419] Rewrite module gpg-agent; rename it to gpg
[Fix #426] Correct syntax error in variable assignment
Ensure that the tmux server is started

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Merge branch 'master' of github.com:sorin-ionescu/prezto