EXP-1485 FIX -- Viewer should have a minimum size

indra/llwindow/llwindow.cpp

indra/llwindow/llwindow.h

indra/llwindow/llwindowheadless.h

indra/llwindow/llwindowmacosx.cpp

indra/llwindow/llwindowmacosx.h

indra/llwindow/llwindowmesaheadless.h

indra/llwindow/llwindowsdl.cpp

indra/llwindow/llwindowsdl.h

indra/llwindow/llwindowwin32.cpp

indra/llwindow/llwindowwin32.h

indra/newview/llappviewer.cpp

indra/newview/llfloaterwindowsize.cpp

indra/newview/llfloaterwindowsize.h

indra/newview/llviewerfloaterreg.cpp

indra/newview/llviewerprecompiledheaders.h

indra/newview/llviewerwindow.cpp

indra/newview/llviewerwindow.h