Additions to page position control

Page position control is derived from selectone.ftl in the default
Alfresco install.  It does not support view mode, since it will only be
used when creating new actions.  This control will hide the manual x/y
coordinate options when any positioning option other than “manual” is
chosen.
Generalized solution for position select

Made position select more generalized so it can be used to hide any
other property input elements when a specific select value is chosen.
Additional code to support dependent selects

More code to support the concept of a dependent value select box.
More work on dependent select code