Cleaned code and improved usage of const

Removed dead code
Introduced const in binders to improve generated binary
Moved binding actions from methods to initialization lists in
constructor.
Activated COMET subsystem

Changed INTERNAL_SELECT to use a remanaged connection system.
Changed code to avoid patches on libmicrohttpd

Changed connection identification system. Now requestor IP and PORT are
used.
Changed to let travis use last libmicrohttpd stable version
Changed a typo
Solved some problems in server stopping
Solved some problems with comet messages' indexing
Added test on long body
Removed extraction of the url at each loop

The url was recalculated at each loop. This was unuseful and really
expensive especially in presence of a big quantity of data to send or
receive.
Update README

Added travis status to the readme
Rename README to README.md

moved readme to markdown
Update README.md

Moved to verbatim to solve layout problems on zencoders tree in readme.md
Enhanced the level of detail of hello_world example
Use MHD_create_response_from_fd for files

Now the library makes use of MHD_create_response_from_fd for files.
This improves the performances because allow to use sendfile on the
socket.
Use AC_SYS_LARGEFILE in configure.ac

This allow to avoid problems when working with FDs on 64bit systems
Avoid memory leak

Avoid a memory leak due to a typo (this is embarassing) in response
completion.
Merge https://github.com/etr/libhttpserver into doc

Conflicts:
	.travis.yml