Changed pesky 'default' property name to use bracket notation so IE 8 doesn't throw a fit.
Fixes bug for pipeline parameters with no default values.
Merged in mflorida/xnat_builder_1_6dev (pull request #83)

Changed pesky 'default' property name to use bracket notation so IE 8 doesn't throw a fit.
Merged in johnflavin/xnat_builder_1_6dev (pull request #84)

Fixes bug for pipeline parameters with no default values.