Maintenance release for v2.4.x

Merge pull request #1529 from dvapelnik/patch-1

[v2.4.12] php5.3.2 not supported short array definition

Maintenance release for v2.4.x

fixes some left issues when nested tree root was used as association.

Maintenance release for v2.4.x

Notable feature added is root as relation for nested set.
The development now moves to 2.5.x and 2.4 versions will be for maintenance only.