Use local version of jQuery when in dev env

Allows people to edit/use local version of dillinger while not connected to
internet.
Highlight markdown blocks based on lang specified

This changes the logic so that the markdown block is highlighted when
there is actually a language prefix in the markdown block.

This will highlight in javascript:
```js
  console.log("sup?)
```

This will not highlight at all:
```
  Not Much
```
Merge pull request #204 from swang/highlight_based_on_lang

Highlight based on lang
Added export with style feature, which allows for optional syntax highlighting in exported HTML files
Merge pull request #209 from kkleidal/master

Export HTML with Style
updated package.json to pull in deps for styled html
updated nav for html with style copy
fixed pathing bug for styled html
0.7.2
minor patch on styled html fix
version bump
Revert sanitize in marked back to false

Closes #202 and #210
Bump version number to 0.7.4
Merge pull request #211 from swang/set_sanitize_to_false

Set sanitize to false