Add XPX language

Add XPX language syntax, auto-complete, snippets and propose a syntax coloring theme to use with syntax.

repository/x.json

@@ -161,6 +161,16 @@
 				}
 			]
 		},
+		{
+			"name": "XPX",
+			"details": "https://github.com/infocosme/sublime_xpx",
+			"releases": [
+				{
+					"sublime_text": ">=3092",
+					"tags": true
+				}
+			]
+		},
 		{
 			"name": "XQuery",
 			"details": "https://github.com/PogiNate/XQuery-Sublime",