move karax source code from 'src' to 'karax'; make karaxdsl work with native Nim; added jjson and jwebsockets modules

tests/nativehtmlgen.nim

@@ -0,0 +1,20 @@
+## Simple test that shows Karax can also do client-side HTML rendering.
+
+import "../karax" / [karaxdsl, vdom]
+
+when defined(js):
+  {.error: "Use 'nim c' to compile this example".}
+
+let tab = buildHtml(table):
+  tr:
+    td:
+      text "Cell A"
+    td:
+      text "Cell B"
+  tr:
+    td:
+      text "Cell C"
+    td:
+      text "Cell D"
+
+echo tab