remove wp-plugin images
better linter settings

enable 'require' keyword by setting 'node' to true
enable '$' global for jQuery
major repo restructuring

The new folder structure in detail:

    src // all source files and libraries except node modules
     |- libs // external dependencies to include
     |- example // example files
     |- sass // SCSS project files
     |- js // application code
     |- img // source images

    dist // will be built entirely from sources
     |- js // production code with vendor libraries included
     |- example // this will be served locally
     |- css // processed stylesheets
     |- font // icon and possibly other fonts packaged with the app
     |- bin // flash and silverlight fallbacks and other binaries
remove mediaelement subtree

Will be included using bower components because html5shiv cannot be
retrieved as an npm package.
Therefore it is convenient to have all three javascript dependencies
in one package manager --> bower.

All development dependencies (gulp and its plugins) are still node
modules.
declare bower component dependencies
update paths to bower components
uncomment unused SCSS include
update readme
re-add editor configuration file

All editors that are able to read the configuration should be able
to autoformat code in a way the linter is happy.

See [editorconfig.org](http://editorconfig.org) for plugins and
further information.
extend jshint configuration and checks
make linter happy, again
update readme

* replace grunt with gulp,
* add link to gulp documentation
* add npm install step to installation
actually reload the developmen server on change
Merge remote-tracking branch 'upstream/2.1.x' into dev_env

Add progress-polyfill to bower dependencies and copy necessary
files in gulp copy task.

Conflicts:
	src/example/embed.html
	src/example/embed2.html
	src/js/app.js
Merge pull request #159 from line-o/dev_env

Enhance Development Environment