- 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!

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/ttr/pkg@88 edb9625f-4e0d-4859-8d74-9fd3b1da38cb