Use new syntax highlighting engine from zyedidia/highlight

This changes all the syntax files in the runtime directory and also
changes how syntax highlighting is done from inside micro.

runtime/syntax/json.yaml

@@ -0,0 +1,24 @@
+filetype: json
+
+detect:
+    filename: "\\.json$"
+    header: "^\\{$"
+
+rules:
+    - constant.number: "\\b[-+]?([1-9][0-9]*|0[0-7]*|0x[0-9a-fA-F]+)([uU][lL]?|[lL][uU]?)?\\b"
+    - constant.number: "\\b[-+]?([0-9]+\\.[0-9]*|[0-9]*\\.[0-9]+)([EePp][+-]?[0-9]+)?[fFlL]?"
+    - constant.number: "\\b[-+]?([0-9]+[EePp][+-]?[0-9]+)[fFlL]?"
+    - constant: "\\b(null)\\b"
+    - constant: "\\b(true|false)\\b"
+    - constant.string: 
+        start: "\""
+        end: "\""
+        rules:
+            - constant.specialChar: "\\\\."
+    - constant.string:
+        start: "'"
+        end: "'"
+        rules:
+            - constant.specialChar: "\\\\."
+    - statement: "\\\"(\\\\\"|[^\"])*\\\"[[:space:]]*:\"  \"'(\\'|[^'])*'[[:space:]]*:"
+    - constant: "\\\\u[0-9a-fA-F]{4}|\\\\[bfnrt'\"/\\\\]"