Add hierarchical data to CAP through XML extensions in schema

Steve Hakusa: To add hierarchical data to CAP, allow XML extensions in the CAP schema through the following change to the .xsd: <any minOccurs="0" maxOccurs="unbounded" namespace="##other" processContents="lax" />
a. Allow such XML extensions at the <info> level, and optionally at the <alert> level. Having extensions at the <info> level would be required in case the hierarchical data is language-specific. Extensions at the <alert> level could cut down on redundancy in the case the data is related to all <info> blocks.

Jacob Westfall: Add extensibility with <xs:any## other minOccurs="0"/>