Append file extension to exported tab files name
Tests: Hide main window before every test

If window is visible and items are added, first item stays is selected
since it was added first -- this is not expected in tests.
Tests: Hide may not work on some window managers

Always show main window (for consistency) and focus first item manually.
Tests: Wait until application is fully started
Check for minimize support only once
Run tests with Travis CI and generate coverage with Coveralls
Coverall: Updated exclude files and compiler/linker flags
Add build scripts for Travis CI
Tests: Test 'help', 'version' and bad command
Tests: Test export with relative path
Added Coveralls badge to README.md
Coveralls: Ignore generated resource files
Print same error if bad function/command is used
Tests: Test create and copy new items
Tests: Test toggle clipboard monitoring
Tests: Test 'copy' command
Desaturate selected item background if item list is not focused
Tests: Fix test for 'copy' command (new item isn't added)
Clean up style sheet code
Tests: Test options