The simulator writes crash_*.dmp relative to its working directory, and
crashpad under crashdumps; the newest one from this run is named, with an
offer to open its folder.
The exit code, read with its signal or NTSTATUS, and the last lines of the
error stream - or of log.txt when it stayed silent. The stream is captured
only while the starter stays to read it.
A build tree kept beside the data can be chosen in the settings, and when no
simulator is found the starter asks for one instead of calling the
installation broken. The simulator now runs in the installation, not in the
folder of its binary, and a binary for the other system is no longer refused.
