Adds emacs foreground and background
This is necessary for the emacs xresources-theme to work with pywal.
! X colors.
! Generated by 'wal'
+emacs*foreground: {foreground}
+emacs*background: {background}
URxvt*foreground: {foreground}
XTerm*foreground: {foreground}
UXTerm*foreground: {foreground}
