Debugging: temporary disabling of trafos

[markusvoelter]

TO be able to track down problems, one should be able to temporarily disable transformations. Adding a "&& false" to the conditions is tediousm and also error prone because it mixes semantics with temporary disabling for debugging purposes.

I suggest adding "disabled" flag to a whole namespace and then not considering any of the trafos inside it.

[slisson]

Maybe provide a UI to disable them without the need to modify and rebuild the transformation aspect.