Make JavaScript ignore rule better

Includes JSHint, JSCS, default JSCS excludeFiles, with additional
improvement with test project VSHost typing faster.

I know this must be the top priority work for you all. Must be someone working on it. I just try to contribute.

For JsHintReporter.cs, extract NotJsOrIsMinifiedOrNotExists() from ShouldIgonre(), to be use in MenuItems/JsCodeStyle.cs and JsHint.cs. I think minified js should never been JSHint/JSCS. For other default ignored js, they will still be ignore at build. But if user select them explicitly and choose to run JSHint/JSCS, we should not stop it.

For LintFileInvoker.cs, I try to stop it run on non project items. But in my debug test, I don't know why it never hit. Still commit it.

Set .jcsc.json excludeFiles to ```["**/*.min.js", "**/*.debug.js", "**/*.intellisense.js", "**/*-vsdoc.js"]```.

For VSHost.cs, original TypeChar will init/cleanup with every single char, I change it into init/cleanup once for a whole string, improve efficiency. And according to http://www.pinvoke.net/default.aspx/Structures/VARIANTARG.html, I change 32 into 16.
This one is not related to others, I don't know whether I should commit/sync/PR this small thing alone, or just put it with other changes like this time.