add addchild feature
Merge pull request #49 from arnaudbey/hotfix

Hotfix &  add addchild feature :)
Adding relations between AbstractWorkspace, AbstractRessource,
ConcreteRessource and Step
Merge pull request #50 from ALouis38/entitiesrelation

Adding relations between AbstractWorkspace, AbstractRessource, ConcreteRessource and Step
add step edit feature and fix some step manipulation bug
Merge pull request #51 from arnaudbey/step_front_edit

add step edit feature and fix some step manipulation bug
some fixes on tree
Merge pull request #52 from arnaudbey/tree_fixes

some fixes on tree