add asserting that issue estimated hours is nil when creating minimal issue
gantt: use content_tag instead of html tag at the tooltip
gantt: use content_tag instead of html tag at the label on the right
gantt: remove redundant empty lines from unit gantt helper test
gantt: use content_tag instead of html tag at subject for project
gantt: use content_tag instead of html tag at the markers
gantt: code layout cleanup to_pdf method of lib/redmine/helpers/gantt.rb
gantt: fix unit gantt helper test fails
gantt: use content_tag instead of html tag at the task bar
gantt: code layout cleanup image_task method of lib/redmine/helpers/gantt.rb
