[TREELIST] Change return value of trelist_ncpaint()...

... from int to LRESULT.
[CHART,EXPAND,MDITAB,TREELIST] Use RedrawWindow() instead of InvalidateRect()...

... whenever we need to invalidate non-client area or child windows too.
[src/resource.rc] Change "FileDescription".
[CHART] Fix copy&paster error in doxygen comment.
[CHART] Rename axis members of chart_t.

primary_axis -> axis1
secondary_axis -> axis2
[CHART] Added support for axis legends.