[Fix #383] Do not set $MANPATH

man dynamically searches for man pages based on $PATH.
[Fix #385] Do not set $INFOPATH
[Fix #381] Remove the path_helper workaround
Use $GNUPGHOME in GPG agent startup

Use the value of $GNUPGHOME, to facilitate moving GPG's home.

This lets users who keep their GPG keyring on external devices or alternate
folders use the gpg-agent autostarting, even if $HOME/.gnupg does not exist.
Add support for nvm
[Fix #351] Set empty keys to an invalid UTF-8 sequence
More control over multiplexer auto-start and SSH

Setting the auto-start style for the screen and tmux modules to 'remote'
automatically starts a session only with SSH connections and to 'local'
only for local terminals. The behaviour when the style is set to a
boolean value is unchanged.