Make debugging tests a bit easier

- Add command-line argument to enable debug logging
- Add command-line argument to open (and leave open) jsconsole
- Try to print error stack traces (although Mocha doesn't seem to like
  them?)

test/components/zotero-unit.js

@@ -32,6 +32,7 @@ ZoteroUnit.prototype = {
 	/* nsICommandLineHandler */
 	handle:function(cmdLine) {
 		this.tests = cmdLine.handleFlagWithParam("test", false);
+		this.noquit = cmdLine.handleFlag("noquit", false);
 	},
 
 	dump:function(x) {