fixed up some issues with the installer and version comparison.
Added a save button to bottom of item input.
For display type links change from attr_match word to attr_match partial
for issue #56
Decided to make the match exact.
Reduce size of the s_site_plugin_s_attribute_type_lookup_map  value
column to fix #63
Reduce size of the s_site_plugin_s_attribute_type_lookup_map  value
column to fix #63
Fix for issue #62.  Failed to perform an upgrade from 1.5.0.8RC2 due to
a version check bug.
fixes to make it clear that upgrades from before 1.5.0.4 are not supported
Fix for issue #65.  Hide any warnings for failure to execute exec
function if its been disabled.
Fix for Amazon UPC lookup not working #66
Fix for Amazon UPC lookup not working #66 properly this time.
Further work on issue #66
Issue #67: Amazon ISBN13 search

This adjusts the search to match what Amazon seems to return when searching
via ISBN13 UPC.
Merge pull request #68 from utopiabound/67-amazon-isbn13

Issue #67: Amazon ISBN13 search