[ENH] Improve usability of the calculation field by using a textarea field

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@49194 b456876b-0849-0410-b77d-98878d47e9d5
[ENH] Offer more flexibility when building fields

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@49195 b456876b-0849-0410-b77d-98878d47e9d5
[ENH] Avoid double visual insertion of relations in the relations tracker field

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@49196 b456876b-0849-0410-b77d-98878d47e9d5