Implement livereload and the Livereload protocol

[Abbe98]

Snowman should support live reloading and the Livereload Protocol/Client . The new command ´snowman watch´ should:

1. watch the file system for relevant changes and bundle those into chunks(every second?)
2. build the site after such changes
3. serve the site over HTTP
4. inform the served site of changes over WebSockets
5. automatically inject the live reload script onto pages (using the view definitions)
6. optionally disable automatic injection and instead provide a template function for the same task

Implementation steps:

1. Depreciate snowman clean and bundle it with snowman build #3
2. Create a built in HTTP server snowman server #4
3. snowman build should be able to build only static files when given the static flag #23
4. ´snowman watch´(tier 1) watch the file system and rebuild and serve the site, if possible build only static files using snowman build should be able to build only static files when given the static flag #23
5. ´snowman watch´ should implement the Livereload WebSockets server and client injection using a template function
6. ´snowman watch´ should automatically inject the Livereload client into pages

Reference:

• https://github.com/omeid/go-livereload
• https://github.com/gohugoio/hugo/tree/master/livereload
• http://livereload.com/api/protocol/