fix ui issues
handle dead proxy refs
make PlaygroundDragElement move search recursively for target
Merge pull request #45 from kived/ui-issues

fix ui issues
Merge pull request #53 from kived/designer-kv-spacing

normalize spacing in designer.kv
make widget_contains check if container is child
Merge pull request #51 from kived/playground-nested-target-fix

make PlaygroundDragElement move search recursively for target
add zoom slider
Merge pull request #54 from kived/playground-zoom

Playground zoom
Merge pull request #47 from kived/speed-cache-proxyfix

handle dead proxy refs in nodetree cache