Major updates to text-slicer plugin

* In the interests of performance and expressiveness, switched to using a Sax parser instead of a DOM implementation.
* Use extensible declarative rules to control the slicing process
* Added new optional set of rules for slicing by heading, where the paragraphs underneath a heading are packed into the same tiddler as the heading
* Added a modal dialogue for specifying parameters when slicing in the browser

plugins/tiddlywiki/sax/files/tiddlywiki.files

@@ -0,0 +1,18 @@
+{
+	"tiddlers": [
+		{
+			"file": "lib/sax.js",
+			"fields": {
+				"type": "application/javascript",
+				"title": "$:/plugins/tiddlywiki/sax/sax.js",
+				"module-type": "library"
+			}
+		},{
+			"file": "LICENSE",
+			"fields": {
+				"type": "text/plain",
+				"title": "$:/plugins/tiddlywiki/sax/license"
+			}
+		}
+	]
+}