Revert "Point travis to the new svn repo of libtorrent."

This reverts commit f1d807da4f328dae39107a4b38048b3354098de9.
Fix functions and macros using to support both Qt4 and Qt5.
Fix translations bundled with Qt.
Update QtSingleApplication.
Fix compilation with Qt5.
Implement alternatives to QHttpRequestHeader and QHttpResponseHeader.
Use the new Http classes.
Migrate the build system to autotools.
Fix Travis.