Declare delayDefault as a variable.
Handle missing transport in send() and close().

The transport might be missing if we are in the
middle of a reconnect attempt.
Drop transport reference after closing.
Support EventSource as a transport.
Use erlang.mk for the build system
Update Cowboy dependency to 0.8.4
Merge branch 'eventsource' of git://github.com/jdavisp3/bullet