Geocoder improvements

1. Clear input field when the home button is used.
2. Change input to type `search` which provides an `x` button for easy clearing.
Geocoder style tweaks
Initial submit for pixel offset scaling by distance.
Added pixelOffsetByDistance to labels.  Added Sandcastle example to demonstrate a usecase.
CSS tweak.
Updated Dynamic layer to support time dynamic Label and Billboard PixelOffsetByDistance.
Refactored PixelOffsetByDistance to instead be PixelOffsetScaleByDistance.  This required the addition of a private member, Billboard._translate that is used by labels to separate glyph translation from pixelOffset settings.
Updated Billboard.computeScreenSpacePosition to use _translate in addition to pixelOffset for screen space positioning.  Updated LabelCollection Unit tests.
Updated DynamicScene to use the pixelOffsetScaleByDistance over the former pixelOffsetByDistance.  Added BillboardCollection, DynamicLabel, and DynamicBillboard unit tests.
Updated Changes.MD.  Minor cleanup.
Added Billboard.setPixelOffsetScaleByDistance SandCastle example.  Minor tweak to Label's pixelOffsetScaleByDistance sandcastle example.
Remove SvgPath in favor of a Knockout binding handler.

Also refactor CSS organization to eliminate duplicate imports.  Shared styles are in shared.css.  Individual widget CSS files, e.g. BaseLayerPicker.css, no longer import anything.  Users are expected to import "widgets.css" to get everything in the common case, or import all of the individual stylesheets, including shared, for each widget that they use, in the uncommon case.
Update CHANGES.
Fix CSS class name for chromeFrameOverlay.
Refactor CameraEventAggregator to create one event handler and aggregate all events.
Remove unused modules.
Add example and test for data binding to a whole object.
Merge branch 'master' into svgPathBindingHandler

Conflicts:
	CHANGES.md
Fixes after testing.
Update ScreenSpaceCameraController input handling in 2D.