DataStore implementation for the ArcSDE 8.x and 9.x spatial gateway.

This implementation is based on the ESRI's ArcSDE Java API. This API is based on a single jar file wich maven downloads automatically and a couple of platform specific libraries (.dll or .so). So we have made an effort in order to this DataStore implementation not being dependant of those native libraries.

The feature set of the ArcSDEDataStore includes feature write support but is actually limited to the inprocess locking manager. Native locking should be developed and will be higly appreciated, so volunteers are wellcome.