Megabytes have shown to be a bit clumsy in the configuration files, so
simply switch to the more useful Gigabytes unit.

Fixes #39

Allow setting the log level explicitly from "Warn", "Info", "Debug" or
"Trace" in the configuration.

Default is "Info", fallback for invalid settings is "Debug".

Fixes #34

The shared approach results in conflicts if the generated class is used
in ATxCommon which is imported in the other projects. This way we can
use the symbols defined via ATxCommon in all depending projects.

The downside is that it slows down the build-process a bit as every
build from a project depending on ATxCommon (read: all others) will
change the generated code and thus force a re-build of ATxCommon and
the project itself. Since building the entire solution is still just
a matter of seconds, that's a fair trade-off.

Otherwise git will complain about binary diffs.

See https://stackoverflow.com/a/10334095/2018314 for details on sharing
resources among multiple projects in a solution.

Refers to #18, #29

Refers to #18, #29

Refers to #29, #18, #28

Refers to #28

Refers to #28

Refers to #29

Refers to #29

Refers to #18

Refers to #18