Conditionally remove associated Term when a Taxonomy is deleted

Ref: #484
Setup a dependent Vocabulary hasMany Taxonomy
Merge branch '1.5-taxonomy'

Closes #484
Fix: Deleting a menu screwup link hierarchy of other menus

Closes #385
Merge branch '1.5-menus'
Add missing `delete` class from row action links
Redirect to current menu when Cancel-ing edit
Avoid "Unknown column `Block`.`chooser`" SQL errors

The `chooser` query variable causes the Search plugin to include it
in the generated SQL. Remove them from Model::$filterArgs and use
PrgComponent::parsedParams() to filter parameters from querystring.
Merge branch '1.5-criteria'
We use Migrations, so remove SQL files for tables
Merge branch 'master' into 1.6