The singinterval module

This is an exercise where the program display an interval and play the first tone. Then the user should sing the interval, and then click a button to hear the correct answer. There is no microphone support yet.

User documentation is in la sekcio nomata "Kanti intervalon".

Here is a minimal lesson file:

header {
  module = singinterval
  version = "3.1.4"
  title = "Thirds"
  ask_for_intervals_0 = 3, 4
  test = "3x"
  test_requirement = "90%"
}