added nsEditProperty
beginning of implementation for SetTextProperties. Currently, it only works if the selection is entirely within a single text node. Currently only
supports bold and italic (mapped to ctrl-b and ctrl-i for testing purposes.)
changed a bunch of interfaces to make things easier, like CreateElement now returns (as an out-param) the element created.
git-svn-id: svn://10.0.0.236/trunk@21760 18797224-902f-48f8-a5cc-f745e15eee43
