CORE-1833 Extend AddColumnStatement to support multipe columns
CORE-1833 Adjust affected multiple columns for AddColumnGenerator
CORE-1833 Change AddColumnChange to generate a "multiple" AddColumnStatement
CORE-1833 Extend DropColumnStatement to support multiple columns
CORE-1833 Change DropColumnChange to generate a "multiple" DropColumnStatement
CORE-1833 Update dbchangelog schema to support dropColumn with multiple columns
CORE-1833 Update inverse for AddColumnChange to use a "multiple" DropColumnChange
CORE-1833 Update inverse for AddColumnChange to use a "multiple" DropColumnChange
Merge branch 'CORE-1833-new' of https://github.com/adangel/liquibase into adangel-CORE-1833-new
CORE-1833 Multiple add/drop support: don't serialize empty "columns" attribute for better compatiblity with 3.2 checksums
Merge remote-tracking branch 'origin/master'