Make a script for creating EOxServer instances

[krauses]

Copies template setting, spatialite init SQL, optional: copy data from autotest ...

[schindlerf]

The script was created with r312.
It copies eoxserver.conf, settings.py and template.map from the eoxserver/conf directory and replaces certain tags (like '<$INSTANCE_ID$>') with given configuration values.

After running the script like

python create_instance.py --initial_data path/to/some_data.json --initpatialite --mapscript-dir=path/to/mapserver -d path/to/somedir TestInstance

one just has to navigate to the newly created directory structure, make a syncdb and the server should be operable.

Currently there is one issue with the initial data. Since not all operating systems support symbolic links (like Windows), the initial_data.json is copied. This implies, that all relative file paths within the file are likely to be not correct anymore.