Improvements in OSM mappings

Support for adding default fields in MappingRule.java
Better handling of lies/plygons and extra options

This commit addresses #513 and #514

Documentation has been updated and the OSM chapter cleaned, removing a section that shouldn't be in the manual
fixed issues with default field names
fixed issue when unmapping polygons

fixes #522
fixed unmaping issues.

-avoid creating null values when unmapping
-handle default fields correctly
added —id option to create-changeset
added osm apply-diff operation and command
make -f parameter in som create-changeset mandatory
reuse username when unmapping osm data
added --geom-name option to geojson import
Added check to geom-name option in import operation.

Now it verifies that the name is not being used.

Also, added --geom-name-auto option in geojson import
added featuretype id to show command output
Added CRS description to output of show command

It includes some refactoring of the CRS serializing functionality
adapted functional tests for shown command
Add support for using different formats from the command line tool
Start on plugin support

Interim commit

Interim commit

Get tests passing
Make Mongo backend an option
Fix syntax error in MongoObjectDatabase
Reduce code duplication for plugin negotiation
Added plugins documentation in man page of init command
Add configuration options to Clone as well
Restore configuration verification during setup