refs #19 extract a common process of createValue()s into createValueCommon().
refs #19 added the mechanism to notify a choice used when a build is queued.
refs #19 FIX: testing whether a task is a project is reverted.
refs #19 added a mechanism to notify a choice used when a build is completed.
Merge branch 'master' into feature/19_addEditedChoice2
refs #19 modified new callback interface more easy-to-use.
refs #19 added adding edited value feature to TextareaChoiceListProvider.
refs #19 Divide addEditedValue as a common component.
refs #19 added a feature adding edited choice value to GlobalTextareaChoiceListProvider.
refs #19 added tests for adding edited value feature.
refs #19 added switch to allow adding edited value to GlobalTextareaChoiceListEntry.