checkbox-touch:get-libs: Add python3-xlsxwriter to export results to XLSX
checkbox-touch.py: Added the export_results method to the app component
checkbox-touch:CheckboxTouchApplication.qml: Add js function exportResults()
checkbox-touch:main.qml: Add view/save results signal handlers

Both XLSX and HTML reports are saved in XDG_DOCUMENTS_DIR
"automatic merge of lp:~sylvain-pineau/checkbox/export-touch-results/ by tarmac [r=sylvain-pineau,zkrynicki][bug=1375591][author=sylvain-pineau]"