TTR version 0.20-1
  Changes from version 0.20-0


NEW FEATURES:

- None.


CHANGES:

- Updated CMO, DPO, DonchianChannel, RSI, and TDI to *explicitly*
  use xts internally.


BUG FIXES:

- Fixed bug in WMA, EVWMA, ZLEMA, and GMMA; results were not being
  reclassed back to their original class.

- Set colnames after cbind call in the following functions: ADX, aroon,
  ATR, BBands, DonchianChannel, EMV, KST, MACD, stoch, SMI, TDI, TRIX.

- Fixed bug in VHF; missing abs() calculation in the denominator.
  Thanks to Jürgen Wurzer for the report!
