[MLLIB] [SPARK-2222] Add multiclass evaluation metrics

Adding two classes:
1) MulticlassMetrics implements various multiclass evaluation metrics
2) MulticlassMetricsSuite implements unit tests for MulticlassMetrics

Author: Alexander Ulanov <nashb@yandex.ru>
Author: unknown <ulanov@ULANOV1.emea.hpqcorp.net>
Author: Xiangrui Meng <meng@databricks.com>

Closes #1155 from avulanov/master and squashes the following commits:

2eae80f [Alexander Ulanov] Merge pull request #1 from mengxr/avulanov-master
5ebeb08 [Xiangrui Meng] minor updates
79c3555 [Alexander Ulanov] Addressing reviewers comments mengxr
0fa9511 [Alexander Ulanov] Addressing reviewers comments mengxr
f0dadc9 [Alexander Ulanov] Addressing reviewers comments mengxr
4811378 [Alexander Ulanov] Removing println
87fb11f [Alexander Ulanov] Addressing reviewers comments mengxr. Added confusion matrix
e3db569 [Alexander Ulanov] Addressing reviewers comments mengxr. Added true positive rate and false positive rate. Test suite code style.
a7e8bf0 [Alexander Ulanov] Addressing reviewers comments mengxr
c3a77ad [Alexander Ulanov] Addressing reviewers comments mengxr
e2c91c3 [Alexander Ulanov] Fixes to mutliclass metics
d5ce981 [unknown] Comments about Double
a5c8ba4 [unknown] Unit tests. Class rename
fcee82d [unknown] Unit tests. Class rename
d535d62 [unknown] Multiclass evaluation
Reformat multi-line closure argument.

Author: William Benton <willb@redhat.com>

Closes #1419 from willb/reformat-2486 and squashes the following commits:

2676231 [William Benton] Reformat multi-line closure argument.