Add application/javascript as a valid mimetype
Add application/javascript as a valid mimetype

Fixes #137 Inlining scripts with type `application/javascript`

bendroid/vulcanize,threeday0905/vulcanize,Polymer/tools,threeday0905/vulcanize,Polymer/tools,Polymer/polymer-bundler,Polymer/polymer-bundler,rcorp/vulcanize,bendroid/vulcanize,Polymer/tools,rcorp/vulcanize,Polymer/tools,Polymer/polymer-bundler