Loading of correlation functions breaks down exceeding a certain number

[weidemann]

Cutoff lies between 130 and 170 number of pages. Loading seems fine as long as the wait bar is moving in the dialogue box and the main window is empty.

PyCorrFit suddenly freezes while trying to display the first page although loading has not been finished.

[weidemann]

Now narrowed: 130 curves works, 132 does not

[paulmueller]

This limitation is the result of a design flaw and directly connected to issue #6. wxWidgets simply can't handle that many tabs. I made some progress by skimming the Page class. It will be possible to replace the whole tabs-idea with something better. The question is how it should look like in the end.