[Fix #689] Use GPG_AGENT_INFO instead of GPG_AGENT_PID

GPG_AGENT_PID may not be defined. Also, source gpg-agent.env before
checking the PID.
[Fix #648] Do not instruct users to call editor-info
[Fix #626] Escape '%' in path
adapt config
use custom theme based on sorin
add option for local zshrc via dotfiles