Add a preexec hook to set the GPG-Agent TTY

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Check for S.gpg-agent to see if gpg-agent is running

From GnuPG changelog:

>  Removed the GPG_AGENT_INFO related code.  GnuPG does now
>  always use a fixed socket name in its home directory.

Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Fix issue with several themes where errors occur
if the git module is not loaded.
Fix Powerline unicode characters

Branch & separator characters are updated to display properly.
[Fix #748] Set grep color for BSD and GNU
Revert "Remove extra git-dir call in git-info and use git_dir variable instead"

This reverts commit 3012c0984b2b3fd97a58ac9dad1ae54efc546e49.
Add `custom` folder plus scripts and aliases.
Activate custom scripts and customise `.zshrc`
Add `prompt_jakob_setup` file and activate prompt.
Customise `zshenv`.
Customise `zpreztorc`.
Update alias definitions.
Update alias definitions.
Enhance aliases.
Enhance zshrc to be used on other boxes as well.
Enhance zshr (add if checks for named dirs etc)
Enhance aliases
Small change to prompt_jakob_setup.
Update alias definitions.
Tidy up aliases (remove lots of systemd aliases)