There is no way to make a line be aligned to common angles, such as 0°, 30°, 45°, 60°, 90°, 180°, 270°, 360° - this is a common feature and would be very useful for creating a ground line, for instance.
That's true. One of the many tasks I have pending on the Illustration component but you are right, it is required! :)
I made a little fixes around this feature, for the next release the option to align lines vertically/horizontally (0 & 90 degrees) will be available for testing.