Fix GitHub links when build locally

Seems RTD was doing some magic on their builds, as all the
edit RST file links would work (except the autogenerated
ones from Python code - not fixed them yet, but tested it
locally).

docs/conf.py

@@ -82,6 +82,17 @@
 # https://sphinx-rtd-theme.readthedocs.io/en/latest/configuring.html
 html_theme_options = {"prev_next_buttons_location": "both"}
 
+# Based on:
+# https://github.com/readthedocs/sphinx_rtd_theme/issues/231#issuecomment-126447493
+html_context = {
+    "display_github": True,  # Add 'Edit on Github' link instead of 'View page source'
+    "github_user": "peterjc",
+    "github_repo": "thapbi-pict",
+    "github_version": "master",
+    "conf_py_path": "/docs/",
+    # "source_suffix": source_suffix,
+}
+
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".