Fixed single-application instance issue using QSharedMemory since the single application class is deprecated
Refocus on existing instance. Changed window name.
Fixed unnecessary include.
Added window_title.cpp
Modified main to improve portability
Implemented show result.
Merge pull request #230 from angathorion/show-result

Show result
Merge pull request #218 from angathorion/single-app-fix

Fixed single-application instance issue
Clean up state after test too

Because content is not serializable by upper layers.
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