Added support for sending HEAD request
Moved deletion of qRestResult outside the if/else in order to prevent leakage.
head request is now asynchronous.
Removed unused parameter, adapted documentation
Added Qt5 compatibility.
Merge pull request #7 from saschazelzer/qt5

Added Qt5 compatibility.
Merge pull request #6 from AndreasFetzer/allow-HEAD-requests

Added support for sending HEAD request
The Result map can be empty on connection errors. Check that.
Merge pull request #8 from saschazelzer/check-for-empty-result

The Result map can be empty on connection errors. Check that.
Started to fix file upload