Revise memory settings

[phdmakk]

The memory settings may be problematic on certain configurations where memory is limited. Revise and reduce the initial memory demands. Original report below:

The problem with T3D was the memory setting: I've removed "-Xss128m" to get it running.
Please note, that the evaluation of the memory size in the batch files never worked well (it stops too early i.e. I've got not enough memory - only "-Xmx384m" for T3Q);
I use "-Xmx768m" for both T3Q and T3D now (i.e. for both I don't have "-Xss128m" anymore; see above).
As a consequence a always need to copy around the batch files as even as admin windows does not let me modify the batch files in in the "programs" folder