Switched to a more intelligent check for differentiating between ranges and points

Signed-off-by: Marko Locher <marko@locher.at>
Added a plugin to load datasets from WMS servers

Signed-off-by: Marko Locher <marko@locher.at>
Updated Readme with information on how to use the WMS plugin

Signed-off-by: Marko Locher <marko@locher.at>