Evas textblock: Added support for default tags.
Evas textblock: Added support for default tags.

This is useful for defining default tags that can be overridden by style.
For example <b> and <i>.

git-svn-id: 6d771e449150288cc513807b7f4d2af31e9482bd@66190 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

TizenChameleon/evas,TizenChameleon/evas,TizenChameleon/uifw-evas,TizenChameleon/evas,TizenChameleon/uifw-evas,TizenChameleon/evas,TizenChameleon/uifw-evas,TizenChameleon/uifw-evas