Initial work on a RetroShare cross-platform service

This doesn't need any interacion of the user at startup, unlike
retroshare-nogui which requires the user to login on the shell this doesn't
even need a TTY.
At startup this just parse command line, read the PGP keyring, look for
available locations, and start listening for JSON API requests.
Another difference with retroshare-nogui is that this is capable to
generate/import PGP identities, generate locations, and in general anything
possible through the RetroShare API.
retroshare-service is suitable also to run it as a system service, even
in very constrained systems such as Android ot a Docker container.
retroshare-service drop support for libresapi so only the new JSON API
is exposed, it will completely obsolete retroshare-android-service once
retroshare-qml-app is ported to the new JSON API.

libretroshare/src/util/rsurl.cc

@@ -16,7 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-//#include "util/rsurl.h"
+
 #include "rsurl.h"
 
 #include <cstdio>
@@ -245,7 +245,7 @@ RsUrl& RsUrl::setFragment(const std::string& fragment)
 
 		if(str[i] == '%' && i < boundary)
 		{
-			decoded << static_cast<char>(stoi(str.substr(++i, 2), 0, 16));
+			decoded << static_cast<char>(std::stoi(str.substr(++i, 2), 0, 16));
 			++i;
 		}
 		else decoded << str[i];