Support Repetition

[ksen0]

• Repetition of individual poses (eg, 5 times on R+L. Easy example: instead of 6 min on Sun Salutation, could make it 1 min on each side, 3x). This means updating duration copy to "x min on each side \n repeat z times" (removed Duration and added newline for relatively more compactness)
• Repetition of flows (eg, 2 times R+L the flow that we have)
• Repetition of just a section of the sequence: eg, Triangle, then Revolved Triangle, then Tri again and rTri again. This is technically already supported by converting Tri + rTri into a flow though...

This could be supported by the following format updates (just a sketch):

sequence = [
    {poses: [
        {
            pose: poses[0],
            duration: 1,
        },
    ], repeat: 3},
    {poses:[
        {
            pose: poses[1],
            duration: 0.5,
        },
        {
            pose: poses[2],
            duration: 0.5,
        },
        {
            pose: poses[3],
            duration: 1,
        },
    ], repeat:2},