Fix memory leak.

The |return| before deleteLater() prevented deletion, while the http request didn't have it's Qt object tree parent set properly.
Use QScopedPointer for request
Parent the QTcpServer
Don't parent the request after all.
Removed tests since it does not do anything useful right now
Removed queryString declaration and documentation. Fixes #25.
Fix URL handling bug and improve URL parsing.

The URL callback was interpreting the data only from one call. The http parser may call it multiple times.
Switched to using http_parser_parse_url and setting fields individually.
Some of these fields are irrelevant in an http server (host, port, fragment), since well behaved clients won't send them, but we might as well handle them since there isn't a significant perf penalty to checking a few constants.
Qt4 compat fix for URL setQuery
only connect for the newConnection event when binding to a port succeeded;
also delete the m_tcpServer when it couldn't listen to the addresss/port;
mark the existing m_tcpServer for deletation when trying to listen to a different port
NULL the m_tcpServer pointer when the data is destroyed;
close the tcpServer and mark it for deletation when the QHttpServer is deleted;
fix typo;
stop using deleteLater in listen() and therefore remove the delayed NULL in tcpServerDestroyed slot;
Added signal to indicate that the send buffer is empty

Without this signal the only non-blocking way of transmitting a file is
to pass all the data at once to QHttpResponse::write(). Memory is
reserved for the full amount of data which multiplies pretty quickly
when there are multiple concurrent transfers.

This signal provides interface for the client code to wait until the
previously written data has been sent and new data can be written to the
socket.

For example a 1GB file can be split into 64k blocks without needing to
load the full file into memory.
Removed debug message on new connections
Merge pull request #28 from Nehmulos/server-bind-fail-patch

Delete QTcpServer on listen() failure.
Style fix for #28.
Use Qt coding style.

clang-format -i -style="{BasedOnStyle: Mozilla, IndentWidth: 4, ColumnLimit: 100, PointerBindsToType: false, BreakBeforeBraces: Linux, AccessModifierOffset: -4}" src/*.h src/*.cpp
with some minor hand editing.