Add simple makefile
Add functions websocket_req:get/2 and websocket_req:set/2

They allow multiple fields in the #websocket_req{} record to be retrieved
or set in a single call.
Fix dialyzer warnings
Merge pull request #12 from jcomellas/jc-multi-get-set

Added functions to simplify getting and setting request fields
Add common test coverage for major functionality
First, awful draft of call/2
Experimental changes for call/2
Merge branch 'add-synchronous-send' of github.com:sanmiguel/websocket_client into add-synchronous-send