Split repo generation functionality out of blenderpack.py

Moved repo.json generation to make_repo.py
Package/addon parsing is getting a bit messy, this can be
cleaned up when we have a clearer idea of what a package is.

For now just make it work.

tests/test_helpers/expected_blinfo

@@ -0,0 +1,13 @@
+{
+    "name": "Extra Objects",
+    "author": "Multiple Authors",
+    "version": (0, 1, 2),
+    "blender": (2, 76, 0),
+    "location": "View3D > Add > Curve > Extra Objects",
+    "description": "Add extra curve object types",
+    "warning": "",
+    "wiki_url": "https://wiki.blender.org/index.php/Extensions:2.6/Py/"
+                "Scripts/Curve/Curve_Objects",
+    "category": "Add Curve"
+ }
+