Properly format the README, using GitHub flavored Markdown

Fixed a couple of spelling mistakes.

Using project version in the OTP app file, to fix rebar dep issue

Add support for appending additional configuration at runtime

Remove direct dependency on sasl

Fix vsn() handling for rebar

Use queue:peek/1 - more efficient than hd(queue:to_list(Queue))

save_response_to_file option extended to support appending to an existing file

inet:gethostbyname/1 might fail for IPv6 literals, therefore check first
if host is an IPv6 address literal.

As specified in the following RFC:  http://www.ietf.org/rfc/rfc2732.txt

* Add rebar
* Move build flags from src/Makefile to rebar.config
* Remove src/Makefile
* Put version in src/ibrowse.app.src
* Remove vsn.mk
* Remove ebin/ibrowse.app
* Change Makefile to read version from src/ibrowse.app.src
* Change Makefile all target to call ./rebar compile
* Change Makefile clean target to call ./rebar clean
* Update .gitignore to ignore ebin/*

Like in synchronous programming, in makes sense to start an inactivity timer only when the caller
does a "recv" call and cancel the timer as soon as data is received from the socket.

This avoids plenty of connection inactivity timeouts. From a logical point of view,
the inactivity timeout should be reset not only only data is received from the socket
but also when the client asks for more data.