Support c-style comments in JSON

Debate rages about whether JSON should have comments. The specification
says it shouldn't but the author of JSON suggested that if you want to
use JSON for configuration, then pipe it through jsmin before parsing.

So that's what we do, using a tiny JSON minifier from
https://github.com/getify/JSON.minify/tree/python

Closes #135

support/test/python/simple_python/.vimspector.json

@@ -1,7 +1,8 @@
 {
   "configurations": {
+    // This is a comment.
     "run legacy vscode-python": {
-      "adapter": "vscode-python",
+      "adapter": "vscode-python" /* coment goes here too */,
       "configuration": {
         "request": "launch",
         "type": "python",