- Fix error C2057: expected constant expression in several array declarations
 - Outline (move from header to source) the IsCandleScaled() and IsViolinScaled() to export them from DLL
 - In fontembedps.cxx, replace unsupported memmem() function by std::search()

png images were truncated when ROOT was running in a small screen attached to the Mac with the graphics window on the the Mac display.

It was reported [here](https://root-forum.cern.ch/t/tcanvas-print-png-outputs-fraction-of-figure-when-canvas-size-is-declared/26011/44).
Thanks Timur to have found this fix.

This was reported here:
https://sft.its.cern.ch/jira/browse/ROOT-8951

Fix from Timur:

1. Add missing TGCocoa::ClosePixmap implementation. Apparently, while scanning for this function
    calls in TPad's code, I forgot to check TPadPainter and thus decided it's never used at all.
2. Make DestroyDrawable more 'atomic' - hide the fact that we first have to 'select drawable'
    (gVirtualX->SelectWindow(id) - note, SelectWindow for pixmap!!!) and then call
    ClosePixmap() - this is due to the old design problem/inconsistency in X11 backend
    and TPad::fPixmapID, which is not a real pixmap ID but some index that points to array
    where the real pixmap id is. Now DestroyDrawable accepts this fPixmapID and does
   all work of selecting pixmap and closing it.

void wait() {
  gROOT->SetBatch();
  TCanvas *c1 = new TCanvas("c1");
  TH1I *h1 = new TH1I("h1","Histogram",100,1,100);
  h1->Draw();
  c1->Update();
  c1->WaitPrimitive();
  cout << "I am here" << endl;
}

This bug was mentioned here: https://root-forum.cern.ch/t/print-saveas-png-draws-axis-title-twice-with-offset/19142/8

This allows for automatic checking overlaps in a given class hierarchy.

TCanvas::Streamer now stream the current palette (the same way as the colors) if it is different from the default one.

This allow to retrieve a plot save in a ROOt file with the exacte same palette used to produce it.
This functionality should also helps JSROOT to produce plot with the correct palette.

Use extra ///<! comment if member should be removed from I/O

Provide cxx files for both

still store of canvas with subpads fails

Problem with std::shared_ptr<TObject>

Still some problem to store canvas with any sub-pads inside

Provide two signatures - with std::array and normal (width,height)

Provide dictionary for all necessary classes, 
canvas painter will not be stored

Qt's meta-object compiler (moc) only understands the -I option for
adding include paths.