To help debug timeout issues interactively

Since the backtrace goes to the console instead, it's confusing to have them in
different places.

Similar to the CMake prepare targets, these are useful when intending to
debug tests or run a server using a standard test configuration, which
requires the testfiles directory to be copied into the binary output tree.

Git revisions are often quoted as 7 hexadecimal digits, so let's do that here
too.

Tidy up usage text, and fix erroneous memory leak reported after calling
PrintUsageAndExit().

Copy built packages into project directory, as AppVeyor won't let us select
files outside of that directory as artifacts for upload.

Add the configuration name to the built package file name, to avoid confusion
between debug and release builds.

Should hopefully help reduce random failures of this test on AppVeyor.

This allows enabling TRACE logging for a specific file (e.g. to enable
exception backtraces for that file) without enabling TRACE globally.

Replace HideFileGuard with LogLevelOverrideByFileGuard.

This will be useful for exception filtering by filename, because MSVC
defines __FILE__ using the full path to the source file, which is
annoying.

Allows us to turn on exceptions for specific files, rather that
filtering them all as Utils.cpp.

This allows enabling TRACE logging for a specific file (e.g. to enable
exception backtraces for that file) without enabling TRACE globally.

Replace HideFileGuard with LogLevelOverrideByFileGuard.

This will be useful for exception filtering by filename, because MSVC
defines __FILE__ using the full path to the source file, which is
annoying.