Add default argument "" to Writer.writeLine
Merge pull request #138 from lucaswerkmeister/patch-1

Add default argument "" to Writer.writeLine
attributes serialization improvements
new html elements added (a, img, ul, ol, li, dl, dt, dd)
head elements serialization fix
Merge remote-tracking branch 'origin/master'
a bunch of text formatting and semantics elements added (i, sub, sup,
small...)
Quick review with Stuwart.
Proccess blocking requests in worker thread.
Define endpoint as enum.
Remove unnecessasry thread blocking.
Validate WS handshake request.
Clean up.
Use less worker threads in test.
Immutability refactor.
WebsocketBaseEndpoint enum.
Add write ByteBuffer to response & use it in serveStaticFile.
Async response.write.
Async file serving.
File path mapper.