Small cahnges needed to make things work with QT5.
urlstr is alredy of type QString
Added video list / download queue; fixes #11. Some classes unit
tested + documented.
Gitignored test build products.
Made aggregate project for tests and enabled `make check`.
Remove unnecessary cleanup from test.

VideoTableModel's dtor already does that.
Fixed memory leak in a test case.
Fix VideoTableModel::removeRows bounds checks.
Removed null checks after `new`.

`new` should throw `std::bad_alloc` instead of returning null.
Fixed operator precedence mistake in a test.
Fix compiler warnings. Mostly unused variables.
Cleanup of MainWindow.cpp.
Moved yle-dl extra options field to detailsWidget.

It's an advanced option that'd be just UI clutter for
the vast majority of users.
Disable download button while the list is empty.
Canceling download process cleanly (with SIGINT!) (fixes #14) and resuming download by default in Linux (fixes #15). Moved some todo tags into issue tracker.
Enable drag&drop of URL's into video list (fixes #18)
Refactored VideoTableModel usage hassle from MainWindow into model class
Added proper download canceling on quit
Added saving and restoring session feature. Fixes #19.

Tested in Linux only.
Fixed single command line download to not restore/save session

Related to #19