Adds a "Restart" option to the file and tray menu.
I downloaded the icon somewhere where it says it is under the LGPL license.
If an options change requires a restart, a popup appears.
Also encryptwallet can now restart.
Command line options will be passed accordingly to the new process, except rescan,reindex etc.
The parent process creates a new child process and exits. This causes the child process to inherit the open file descriptors. (Only for *nixes.) So I had to add some "fcntl" to prevent file descriptor leaks. There could still be some leaked, for example on my system with qt5, leaked descriptors for "/dev/ati/card0" get added every restart. But we dynamically raise file descriptor limit and exit if not enough available. On my system the max limit is a million by default, so I doubt that this will cause a problem to anybody, and even if, we would just exit with "Not enough file descriptors available."
Windows does not have this issue, because there is a flag for this and QProcess::startDetached calls CreateProcess() with bInheritHandles=false. I checked the qt source code and tested this with process explorer on windows, and indeed, no handle leftovers there.
Tested
- Linux (qt4.8, qt5.2)
- Windows 7 64bit qt5.2 (32 and 64 bit executables)
