Exceptions raised in wms_standalone server lose their context

[Joern Ungermann]

When bugs in the WMS server occur and Exceptions are thrown, these are catched and reraised in a way that the origin of the Exception is lost. This makes the debugging quite hard, as it is unclear which portion of the code is responsible.

[Reimar Bauer]

Fixes issue #9

Changed the way the exceptions is reraised to preserve the context.

→ <<cset 3d11121f989c>>