fix displaying of marker tree
Use treetwisty.svg again because bug 764299 has fixed the SVG perf problem. Reverts commit 505cb07f1849114fc0b43ac7a8b9d91922d2a90e.
Capture the mouse during histogram selection dragging.
Merge pull request #26 from bgirard/tree-styles

fix displaying of marker tree
Merge pull request #27 from mstange/hidpi-toggle

Use SVG treetwisty image again for nice HiDPI appearance
Merge pull request #28 from mstange/histogram-mousecapture

Histogram mousecapture