Avoid compilation of GeomAlgo_Splitter class with newer OCCTs

[rainman110]

GeomAlgo_Splitter is a copy from the Salome project and is licensed under the L-GPL. This makes it hard to use TiGL from commercial code.

Since OpenCASCADE 7.1.0, the algorithm is intergrated into OCCT as well. Thus, we should this one instead, which can be then dynamically linked. The GeomAlgo_Splitter then should not be compiled into TiGL anymore.

[joergbrech]

@rainman110, is this still an issue?

[rainman110]

Yes, it is. Since we are now using OCCT 7.4, we could remove the class. Only problem would be, that we cannot use an old OCCT / OCE anymore.