Add Numix/4chan/Twitch themes (#140)

* Add Numix theme
* Add 4chan themes: Yotsuba, Yotsuba B, Tomorrow and Photon
* Add Twitch theme

data/themes.yml

@@ -179,3 +179,9 @@
 - { colors: '#333333,#1E2320,#709080,#FFFFFF,#1E2320,#FFFFFF,#F0DFAF,#CC9393', name: 'Dark Zenburn'}
 - { colors: '#ebe5da,#d6b498,#c2804a,#ffffff,#b09582,#000000,#009917,#d95b5b', name: 'Latte Time'}
 - { colors: '#f4f6f9,#e0e5ee,#d8edff,#0070d2,#e0e5ee,#16325c,#4bca81,#c23934', name: 'Lightning'}
+- { colors: '#333333,#2d2d2d,#2d2d2d,#f9f9f9,#2d2d2d,#dedede,#d64937,#d64937', name: 'Numix' }
+- { colors: '#ffffee,#f0e0d6,#f0e0d6,#800000,#f0e0d6,#800000,#0000ee,#0000ee', name: 'Yotsuba' }
+- { colors: '#eef2ff,#d6daf0,#d6daf0,#000000,#d6daf0,#000000,#34345c,#34345c', name: 'Yotsuba B' }
+- { colors: '#1d1f21,#282a2e,#282a2e,#c5c8c6,#282a2e,#c5c8c6,#5f89ac,#5f89ac', name: 'Tomorrow' }
+- { colors: '#eeeeee,#dddddd,#dddddd,#333333,#dddddd,#333333,#ff6600,#ff6600', name: 'Photon' }
+- { colors: '#7d5bbe,#6441a4,#6441a4,#ffffff,#6441a4,#ffffff,#6441a4,#6441a4', name: 'Twitch' }