Travis requirements to get sorl 11.12.1b and fix django 1.7 beta from tarball instead of pip

.travis/requirements.txt

@@ -2,7 +2,10 @@
 Markdown>=2.2.0
 django-sekizai>=0.7
 # Switch to Pillow and the dev version of sorl v12
-git+https://github.com/mariocesar/sorl-thumbnail.git
+sorl-thumbnail>=11.12.1b
+Pillow
 # Notification system
 django-nyt>=0.9
+django-mptt>=0.5.3
+six
 

.travis/requirements_1.7.txt

 -r requirements.txt
-Django>=1.7,<1.8
+#Django>=1.7,<1.8
+#Get the 1.7.b4
+https://www.djangoproject.com/download/1.7.b4/tarball/