Xresources: don't set terminal name

Setting the terminal to xterm-256color makes some keys (e.g. home and
end) non-functional. rxvt sets the terminal type automatically.
xsession: disable the bell + fix urxvtd

Disable the bell and run urxvtd in the background.
Set PATH in bash and X

Previously the PATH environment variable was set only for shell
sessions. Now the environment is set in a separate script that is
sourced from bash scripts and xsession.
Merge branch 'master' of github.com:grn/dotfiles