Corrects the handling of the image verification status message

Adds the 'verify' method to os_install.rb to properly return the verification status message
Moves the verification status logging and message to base.rb from the individual image handlers
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
Adding sorting for tag_matchers table output

Sorting is configured as follows:
tag matchers    : key
Corrects alignment of column header for colored results

Remove color codes when collecting the max length of a column item.
Clean up duplication of hash_array sorting code.
Merge pull request #206 from mtnbikenc/issue-201

Fixes #201 Adding sorting to slice table output
Merge pull request #210 from mtnbikenc/issue-209

Fixes #209 Corrects the handling of the image verification status message