The old syntax uses a series of Key=Value pairs, instead of
the more standard "--key value" syntax.
This is required so that the old Mendeley Desktop versions can
launch the new updater.
* Add FileOps::fileName() to get the base name for a file
* Add ProcessUtils::runSync() to run a process, wait for it to exit and then
return the status code from that process.
* Change ProcessUtils::runAsyncUnix() to use execvp() in order to search PATH
for the specified binary if the filename is not absolute.
