Debug memory leak in IMGUI Demo

[ZahlGraf]

The IMGUI Demo example does not free up all memory allocated internally for IMGUI.
It is important to debug this and to find out, if this is an issue of IrrIMGUI or the Example program, or if this is an issue of IMGUI.

[ZahlGraf]

The memory leak in the Demo example is a false negative. It comes from static data inside the Demo-Window function from IMGUI. When the Demo-Window function uses these data the first time, it allocates dynamically memory from the heap.
However static variables are deleted during program exit, thus the memory is still allocated when IMGUI shutdowns and the memory consistency check is performed. So we get an error message for that, but it is not a real error.

There is no way to force the application to delete this static variable earlier, so the only possibility is here to disable the memory leak detection to not get false negative error reports.

[ZahlGraf]

The static memory is allocated at line 674 of file imgui_demo.cpp:

static ImVector<float> values; if (values.empty()) { values.resize(90); memset(values.Data, 0, values.Size*sizeof(float)); }