Implements ranch_transport:connect/4.

Adds a transport connect method that takes a timeout, with implementations for both ssl and tcp connections.
Update erlang.mk
Update erlang.mk again
Remove the confusing doc folder

All documentation is in README.md, guide/ and manual/ now.
Add example using gen_server
Update tcp_echo example to use erlang.mk
Gracefully shutdown when stop_listener/1 is called

Implements the `shutdown` option as documented previously.
Merge branch 'tcp_echo_example_updates' of git://github.com/joshrotenberg/ranch
Fix small issues and style of the examples
Examples must follow master
Add an error report when a connection process fails to start

Becoming closer to a standard supervisor everyday.
Merge branch 'connect_timeout' of git://github.com/heroku/ranch
Add transport options linger, send_timeout, send_timeout_close
Get rid of a ton of pointless comments

All of it can be found in the manual, which defines what the
code must do, and is always up to date unlike the code comments.
Add Transport:shutdown/2

Allows closing the socket in one or two directions.
Ranch is supported on R15B01+

Add a script that runs the test suite on all Erlang versions
starting from R15B01.

R15B is not supported due to issues with sendfile.
Add support for R16B03