feat(accordion): add basic accordion display directive

- accordion element contains accordion-item elements.
fix(tileEditorInput): greedy mousewheel handler

- don't consume mousewheel events unless they're directed at the tile editor canvas.
feat(tileSetTilePicker): show current selection

 - also scale 16x16 tiles up to 2x to allow appropriate fat thumb support on touch screens
feat(tileEditorView): accordion tile set picker

- show tile sets in an accordion style with a max height and scrolling content.
feat: update to typescript 1.3
Merge branch 'accordion-tileset-picker'