Save JSON configuration prevalue as chunks

As described in issue #34 (imulus#34) the Archetype JSON configuration
quickly exceeds the 2500 characters allowed by Umbraco prevalues.
To circumvent this problem we'll chop the Archetype JSON configuration
into several prevalues of max 2500 characters before saving the datatype
to the database.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into prevalue-chunk
Merge branch 'master' into prevalue-chunk
Merge branch 'master' into prevalue-chunk
Fix deserialization of RegEx enabled properties

Fix type mismatch for RegEx (introduced in 6e50301 - my bad, sorry)
Add/move dynamic classes for targeting of custom behavior
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into prevalue-chunk
Fixed merge

Namespace Archetype.Umbraco.PropertyEditors was changed to
Archetype.PropertyEditors in PR #125