Change Operation to modify xml_node instead of xml_document
Add static consts to identify xml tags for tasks and other data
executeTransaction now receives xml_node instead of xml_document
Add getter for tasks and data node
getAllTask and onTransactionCommit make use tasks node getter
XML Handler getters now require xml_document as parameter

For onTransactionCommit temp xml_document
Modify test to adhere to the changes in xml structure, add some explanation
Changed iterator

Conflicts:
	You-GUI/task_panel_manager.cpp
Set to element before end
Changed to another method.
Removed unnecessary include.
Changed dependency insertion again
Fixed some include stuff
Syntactical change
Fixed compile issue
Tiny fix for #220
Merge pull request #221 from angathorion/dependency-insertion-fix

Dependency insertion fix (container agnostic)
Add BranchOperation
Add test for BranchOperation
Completely refactor getTasksNode and getDatanode