Data setter mechanism added.

The data setter module provides a convenience mechanism for allowing data
conditions to be specified and passed in to a page or activity definition.
Text fields, select lists, checkboxes and radios can be populated based on
the data indicated.

The data setter is the beginning stage of a more comprehensive data builder
mechanism.
Data builder mechanism added.

The data builder module provides a convenience mechanism that builds off of
the data setter module. The data builder is used to build data from common
repositories of test data, which will be stored in yaml files. Symbiont will
look for a default data file but you can specify your own as well.