Added Eclipse tutorial to site

Added "Eclipse step by step guide" to
http://www.gwt-openlayers.org/user-reference.html

Added link to showcase in topbar

Added binary downloads
additions for transition effects, enhanced enum and extended GridLayer to reflect OpenLayers API at http://dev.openlayers.org/docs/files/OpenLayers/Layer/Grid-js.html#OpenLayers.Layer.Grid.transitionEffect.
Merge pull request #3 from sebasbaumh/transitioneffects

additions for transition effects
Fixed typo storke-->stroke.
This was fixed in the old version at BitBucket, but is not in the new version at GitHub.
Original author was andypower <nazzareno.sileno@geosdi.org>
zoomlevel, resolution and scale handling:
Added getters for resolution and scales to Layer (http://dev.openlayers.org/apidocs/files/OpenLayers/Layer-js.html).
XYZ layer can get an offset for zoomlevels and a range of zoomlevels can be set.
This allows to use XYZ sources, which do not contain all zoomlevels or should be limited and corresponds with http://dev.openlayers.org/apidocs/files/OpenLayers/Layer/XYZ-js.html.
Merge pull request #5 from sebasbaumh/zoomlevelresolution

zoomlevel, resolution and scale handling:
Merge pull request #4 from sebasbaumh/typostorke

Fixed typo storke-->stroke.