Fixing orx:meta element bug and support for new Collect features

[The bug.](https://groups.google.com/forum/?fromgroups=#!topic/opendatakit-developers/2k_9mGHgRRs)

New features:
prompt types for the uri:... properties documented at the bottom of the [odk examples page](http://opendatakit.org/help/form-design/examples/)

A computed instanceName setting can be provided on the settings sheet for automatically naming forms.