Provide support for expressions across all form elements

bstansberry: <inet-address value="${jboss.bind.address:127.0.0.1}"/>
[3:11pm] hbraun: the first part is resolved from system properties?
[3:11pm] hbraun: the later is the default?
[3:11pm] bstansberry: yes
[3:11pm] hbraun: wicked
[3:12pm] bstansberry: but what's stored in the model is a ModelNode of type ModelType.EXPRESSION
[3:12pm] bstansberry: and the metadata for the attribute includes "expression-allowed" => true
[3:12pm] hbraun: ok
[3:13pm] hbraun: did you just want to raise my attention?
[3:13pm] bstansberry: those really should appearing all over the place
[3:13pm] bstansberry: yeah
[3:14pm] bstansberry: really a very heavy % of attributes should allow expressions
[3:14pm] hbraun: damn
[3:14pm] hbraun: i need to think about the implications
[3:14pm] hbraun: for the UI
[3:15pm] hbraun: so attributes actually allow multiple types?
[3:15pm] hbraun: i.e. string or expression
[3:15pm] bstansberry: yes, X or expression
[3:15pm] bstansberry: where X is the "type" = X in the metadata
[3:16pm] hbraun: do we have proper setters for expression values?
[3:16pm] hbraun: in the DMR lib I mean?
[3:16pm] hbraun: or how does it currently work
[3:16pm] hbraun: ?
[3:16pm] bstansberry: ModeNode.setExpression(String s)
[3:16pm] hbraun: i.e. how do you create an add operation that contains an expression?
[3:16pm] hbraun: ah, guess we didn't port that to the GWT lib yet