Fixes change:schema binding + adds spec

Conflicts:

	lib/assets/javascripts/cartodb/table/menu_modules/filters.js
	lib/assets/test/spec/cartodb/table/menu_modules/filters.spec.js
Improves change:schema test

Conflicts:

	lib/assets/test/spec/cartodb/table/menu_modules/filters.spec.js
Some fixes in user relocation scripts

Added methods to return the db name and username prefixes depending on
the running environment.
Don't rename db username in origin when performing the db dump.
Replace db name and username in sql dump by the ids of the destination
user.
Convert privacy value to integer before inserting it in the db.
Fixed the method that returns from redis all the tables in a database.
Fixes error on OSM loader

Adds a config entry for osm2pgsql port.

osm2pgsql relies on prepared statements, and those don't play
well with transaction pooling (pgbouncer for example):

http://pgbouncer.projects.pgfoundry.org/doc/faq.html#_how_to_use_prepared_statements_with_transaction_pooling

This change provides a configurable port for osm2pgsql.
NEWS.md
Fixed database_username function