Support global %maxcore option in the input file generation

[danielhollas]

It looks like the ORCA input file format is not really consistent with itself. Usually, input blocks start with %block_name and end with end, but there are exceptions to this. One of them them is the global memory setting, which needs to be on one line like this.

%MAXCORE   4000

It seems that the current plugin does not support this format. We can either add a special input node (of type Int) that would set the global memory and then special case it in the input generator, or we can make a general way to support this special syntax.

[ezpzbz]

As far as I remember from the manual, there are ways to define such inputs consistent with the current implementation. I am against having exceptions in the plugin unless the feature is necessary to have and there is no workaround for it.

Let's have a look @danielhollas at the manual and find a solution. Either way, we can have a note in the documentation if needed (possibly adding an example too).

[danielhollas]

Back when I was looking into this, the only solution I found was defining maxcore within each method section (e.g. within the tddft block). This works and it is what I use now in my app. The global option would be more convenient, but it is not currently a big priority for me. I agree that having an exception just for this is not great. Perhaps the memory option could live in the settings dictionary? In any case, let's leave this open so that we have this issue documented.