Vertical scroll renamed to Horizontal scroll
- switching to hSizer if scrolling horizontal
- add expand flag to allow items to stretch vertically
Reduced update interval of ArtworkPanel
Merge pull request #546 from NielsZeilemaker/horizontal_scroll

Vertical scroll renamed to Horizontal scroll
fix debug frame test
Merge pull request #547 from LipuFei/fix-dispersy-frame

fix debug frame test