Fix for creating new blog - if textyle was created before dan's changes, the insert would fail with NOT NULL constraint for textyle_content field. I fixed it by adding default value for textyle content = empty string.

git-svn-id: http://xe-textyle.googlecode.com/svn/trunk/textyle@586 bebf4043-ad85-6e1f-322f-7830e3d0fd93