add vectorized call to R's DTW

Not suSimilar args are passed to R's dist function as in RDTW, but
it's not clear they're having an effect. The vectorized version
returns a matrix with the distance between each pair, but the values
are not the same as in the normal RDTW function so tests are needed.
add vectorized DTW classifier, fix in getSequences to cull short trips

Open-ended DTW requires query sequence to be shorter than templace
sequence, so we have to remove trips that are shorter than nPts long.

Started vecDTWClassifier to call dtw.vecRDTW - still need to test that
function to see if results are ok, but for now let's see how well the
classifier does.