Fixes microsoft7 maps provider and add it to tests

- fixes calculations on getBounds, setBounds, getCenter, getZoom
- fixes html info bubble for microsoft7 maps
- sets .lng property when extending BoundingBox
Refine check if Bing maps are loaded

Better to check Microsoft.Maps.Map because that is what we are using
and it may not be loaded still, despite the fact that Microsoft and
Microsoft.Maps are defined.
Merge branch 'microsoft7_provider'
LatLonPoint.toPixels

Adds LatLonPoint.toPixels, which returns the position of the point in
pixels according to map containing DOM element.