Emacs: Add recursive dired listing

From Craig Andera,
https://github.com/candera/emacs/blob/835318fb4ee3aa801256f3e0e9e605d6fb10148f/init.el#L554-L567
Emacs: custom key to insert src block
Emacs projector theme: gray background for SRC blocks
Bash: add pgrep alias
Bash: GPG agent and 'pass' password store
Emacs custom: update "safe" theme hashes