Add pos and length so that position in the loop can be determined

[xconverge]

Pretty simple getters I found useful to calculate where in the loop I am to display, I did not find IsNearBeginning to be sufficient for my needs.

I am using it like this

  float percentageDone = 100.0 * (m_looperL.GetPos() / m_looperL.GetRecSize());

The formatting changes were so minor I thought it didn't impact the reviewability of the PR

Also added variable playback speed option

[stephenhensley]

Looks good to me! Definitely helpful additions!

Thanks for the contribution!