Contribution from Yash to solve #250 and make BallBound usable.
Tests for ball trees and BallBound<> by Yash, to solve #250.
Point out that there is a known bug.
Fix normalization bug (transpose); Some more comments.
Some notes on some things I've done.
Additional things that have changed.  I incorrectly wrote in the last commit
about stuff "I had done" but I'm not sure why, given that each of these
contributions are from people who are other people.
Ball tree tests for EMST.
Initialize reverseStepCount to 0 to avoid memory issues.
Fix an uninitialized value.
Increase tolerances a little bit, because they were failing in some cases.
For each random dataset, ensure that the size of the implied user/item matrix is
numUsers by numItems by manually setting the last element.  Some formatting and
const-correctness fixes.  Also, increase the number of iterations for the
optimization test since it didn't seem to be converging (hopefully the specific
number of 10 passes over the data was not chosen for a particular reason).
Patch from Sumedh: fix some uninitialized values.
Patch from sumedh: Mat::row_col_iterator
Patch from Sumedh: more tests for SVD
Patch from Sumedh: tests for row_col_iterator
R* tree bug fixes.
Propagate HISTORY.txt change to trunk.
New tests added for adaboost.
code cleanup for R tree
Update documentation.