Several RF implementations are now included

progress information added

Update tests after randomForest package update

• update all tests because randomForest package has been updated and behavior
  with set.seed() has changed (and hence crashing all tests of VSURF)
• add PM10 data into the package

Tests added to the package

This is a minor update, which essentially adds some tests in the package.

v1.0.0 Major update

Lots of changes documented in the NEWS file.

• Functions *.parallel removed. Main functions run in parallel with para=TRUE.
• Functions names changed: VSURF.thres -> VSURF_thres, VSURF.interp -> VSURF_interp, VSURF.pred -> VSURF_pred