Add integration tests for EditorDocument class

[gohabereg]

By integration tests we need to check that all calls are being propagated into child entities through the whole model

All checks should be done by assertion on serialized method of EditorDocument

Method	Comment
constructor	check that the whole model is initialized with data passed to constructor
addBlock	check that block is created and initialized with data passed to the method
updateValue	check that value of related ValueNode is updated
updateTuneData	check if related BlockTune value is updated
insertText	check that related TextNode value is updated
removeText	check that related TextNode value is updated
format	check that related TextNode value is updated
unformat	check that related TextNode value is updated

Final test case should assert on "real-life" scenario like adding/removing some blocks and updating their nodes