Updated Clipboard to use selection instead of asking views
EditorGameAssets sets components ignores

Clipbard also needs to serialize objects with editorGameAssets, so Save
can't set the ignores no more.
Updated Copy, Cut and Paste actions
Created ModelEntityCopyListener to copy/cut/paste model entities
Changes after refactor
Merge pull request #523 from anserran/copypaste

Updated Copy-Paste mechanism to use selection