Add ability for hierarchyviewer to output displaylist info

Clicking on a node in hierarchyviewer1 and hierarchyviewer2 and then
clicking the new "Dump DisplayList" button will cause the display
list for the selected node (including its children) to be output into
logcat.

Change-Id: Iad05f5f6cca0f8b465dccd962b501dc18fe6e053