Add gruvbox theme

Inspired by the vim gruvbox color scheme.

themes/gruvbox

@@ -0,0 +1,82 @@
+[colours]
+bkgnd=Grey11
+titlebar=Grey19
+titlebar.text=Grey66
+titlebar.brackets=Grey39
+titlebar.unencrypted=IndianRed
+titlebar.encrypted=Grey66
+titlebar.untrusted=yellow
+titlebar.trusted=Grey66
+titlebar.online=DarkOliveGreen3
+titlebar.offline=IndianRed
+titlebar.away=Grey66
+titlebar.chat=Grey66
+titlebar.dnd=Grey66
+titlebar.xa=Grey66
+
+statusbar=Grey19
+statusbar.text=Grey66
+statusbar.time=Grey66
+statusbar.brackets=Grey39
+statusbar.active=Grey66
+statusbar.current=Yellow
+statusbar.new=bold_white
+main.text=NavajoWhite1
+main.text.me=NavajoWhite1
+main.text.them=NavajoWhite1
+main.splash=yellow
+main.help.header=yellow
+main.time=Grey66
+
+input.text=NavajoWhite1
+subscribed=DarkOliveGreen3
+unsubscribed=IndianRed
+otr.started.trusted=DarkOliveGreen3
+otr.started.untrusted=yellow
+otr.ended=IndianRed
+otr.trusted=DarkOliveGreen3
+otr.untrusted=yellow
+online=DarkOliveGreen3
+away=Grey39
+chat=DarkOliveGreen3
+dnd=IndianRed
+xa=Grey39
+offline=IndianRed
+incoming=yellow
+mention=yellow
+trigger=yellow
+typing=yellow
+gone=yellow
+error=IndianRed
+roominfo=yellow
+roommention=yellow
+roommention.term=yellow
+roomtrigger=yellow
+roomtrigger.term=yellow
+me=yellow
+them=DarkOliveGreen3
+roster.header=yellow
+roster.chat=DarkOliveGreen3
+roster.online=DarkOliveGreen3
+roster.away=Grey39
+roster.xa=Grey39
+roster.dnd=IndianRed
+roster.offline=IndianRed
+roster.chat.active=DarkOliveGreen3
+roster.online.active=DarkOliveGreen3
+roster.away.active=Grey39
+roster.xa.active=Grey39
+roster.dnd.active=IndianRed
+roster.offline.active=IndianRed
+roster.chat.unread=DarkOliveGreen3
+roster.online.unread=DarkOliveGreen3
+roster.away.unread=Grey39
+roster.xa.unread=Grey39
+roster.dnd.unread=IndianRed
+roster.offline.unread=IndianRed
+roster.room=DarkOliveGreen3
+roster.room.unread=DarkOliveGreen3
+roster.room.mention=DarkOliveGreen3
+roster.room.trigger=DarkOliveGreen3
+occupants.header=yellow
+receipt.sent=IndianRed