Created Custom Activity domain
Merge branch 'CORE-1104' of github.com:frontlinesms/frontlinesms2 into CORE-1104

Conflicts:
	plugins/frontlinesms-core/grails-app/domain/frontlinesms2/CustomActivity.groovy
Merge branch 'CORE-1104' of github.com:frontlinesms/frontlinesms2 into CORE-1104

Conflicts:
	plugins/frontlinesms-core/grails-app/domain/frontlinesms2/CustomActivity.groovy
Removed Type variable from Step class and subclasses
Added tests for CustomActivity.groovy
Merge branch 'CORE-1104' of github.com:frontlinesms/frontlinesms2 into CORE-1104