Remove built dependencies

This commit removes libsass and Pillow from the setup.py dependency list. This greatly improves install performance and also means that the basic Wagtail installation is pure-python (so no build tools need to be on the end users host machine).

None of these dependencies are directly called from within Wagtail so the start project command continues to work correctly.

setup.py

@@ -30,11 +30,9 @@ PY3 = sys.version_info[0] == 3
 install_requires = [
     "Django>=1.7.0,<1.8",
     "django-compressor>=1.4",
-    "django-libsass>=0.2",
     "django-modelcluster>=0.5",
     "django-taggit==0.12.2",
     "django-treebeard==3.0",
-    "Pillow>=2.6.1",
     "beautifulsoup4>=4.3.2",
     "html5lib==0.999",
     "Unidecode>=0.04.14",

wagtail/project_template/requirements.txt

@@ -1,6 +1,8 @@
 # Minimal requirements
 Django>=1.7,<1.8
 wagtail==0.8.5
+django-libsass>=0.2
+Pillow>=2.6.1
 
 # Recommended components (require additional setup):
 # psycopg2==2.5.2