Fixes #201 Adding sorting to slice table output

Table sorting is added to the slice outputs and performs a case-insensitive sort for strings or numerical sort on fixnum.  The output for the images slice has been converted to a table format vice the item format to improve readability.

For each of the slices, sorting is configured as follows:
active_model: node_uuid
broker: name
broker template: plugin
image: filename <- this is the iso filename
model: label
model template: name
node: timestamp
policy: line_number
policy template: template
tag: name