new FT test_theme for theme switcher functionality; theme-switcher content added to home.html, several dashboard views & urls, all appropriate ITs & UTs; lyric user model saves theme (migrations run); django-compressor and django-libsass libraries added to dependencies

src/core/context_processors.py

@@ -0,0 +1,4 @@
+def user_theme(request):
+    if request.user.is_authenticated:
+        return {"user_theme": request.user.theme}
+    return {"user_theme": "theme-default"}