List of changes:
1. authorship.module:
a) authorship_form_alter(): authorship controls in the comment-form
b) authorship_form_alter(): authorship controls in the comment-admin-settings
c) authorship_comment(): implementation of hook_comment()
d) authorship_nodeapi(): INSERT is performed only when at least one of {$node->authorship, $node->profile_real_name} was specified. No point of storing empty rows.
e) typo 'vlaue' changed to 'value' (inside authorship_form_alter() )
2. authorship.install:
a) authorship_install(): updated DB structure
b) authorship_update_2(): to update previous installations of the Authorship module
c) authorship_uninstall(): implementation of hook_uninstall()