Removed the `extend <BasePeer>` in PHP5PeerBuilder since it's a bug.
Removed limitation where we can only move branches inside the same scope.

It's now possible to move branches over different scopes.

Added `setNegativeScope` to the peer class, which moves the branch so we have negative left/right values.
`isDescendantOf` returns now `false` if the parameter is in a different scope instead of throwing an exception.
In `moveSubtreeTo` we detect now whether the scope is different or not and use then (if different) the `setNegativeScope` and own `shiftRLValues` calls to move the branch  to the correct place.

Adjusted the tests `testMoveToLastChildOf`, `testMoveToFirstChildOf`, `testMoveToPrevSiblingOf` and `testMoveToNextSiblingOf` so it tests more cases, especially the new feature.
Coding style, comments adjusted and removed unused variable.
`setNegativeScope` does not return anything.
Remove one more unused variable.
typo in the comment
Docblock fixes and one assignment typo
addHaving()'s parameters are the same as those of getCriterionForCondition
Pulled out assignment typo to clean up PR
break on first validation error,...

because any further validation won't affect the result anyway. saves a few cpu-cycles.
More docblock fixes.
Fixed #601.

The error_reporting level `E_ALL & ~E_NOTICE` in PHP generates some failures in the test suite.
This is the fix for that and for the `PgsqlSchemaParserTest` fatal error, both mentioned in #601.
Merge pull request #602 from MArcJ/fix-errorreporting

Fixed #601.
Merge pull request #599 from staabm/patch-2

break on first validation error,...
Merge pull request #597 from bjdelange/master

Docblock fixes
Merge pull request #583 from MArcJ/nested-mv-branch

[Nested set] Removed limitation where we can only move branches inside the same scope.
Prepare 1.6.8 release
Bump version to 1.7.0-dev
Merge pull request #574 from MArcJ/master

Removed the `extend <BasePeer>` in PHP5PeerBuilder since it's a bug.
Fixed #603