Simplify code when set parent of children in CAttribute.
Set parent of attributes in CComplexObject in the same way.

So we have back links in constraint tree.
Tests of parent set.
Add path calculation.

Always set @path doesn't require now.
Use constaint parent to calculate path.

(In the future initializing path directly may be removed from adl parser)
Fix parent assignment through inject method.
Merge pull request #18 from dem/develop

Parent attribute in constraints and path calculation