Move cassandra model stuff to its own file
Fix src files to use CassandraModel
Fix tests
Remove System.out.printlns
Move safeDiv to Util
Include rate in counter rollups.

* CounterRollup was no longer a single value, which means SingleValueRollup and its serializer no longer had a purpose. Gone.
* Noticed that set rollups are the same as BasicRollup. Cleaned things up a bit.
get rid of numSamples in counters.
SingleValueRollupTest -> CounterRollupTest
include rate in unit tests for counter.
use the right constant for set rollup tests.
address PR comments. fix spacing, introduce constant, change order of comparisons in .equals.
Merge pull request #183 from gdusbabek/counter_rates

Include rates with counters.
Merge pull request #180 from lakshmi-kannan/bf_get_column_family_from_gran_and_type

RFR: Get column family given granularity and rollup type
Make CF mappers private
Merge pull request #184 from lakshmi-kannan/bf_cleanup_cf_mappers

Make CF mappers private
make dockerfile work again
undo wildcarding. find a solution that works later
work with new all-modules target
Merge pull request #187 from fourk/fix_docker

Fix dockerfile to work again.
fix intermittent test failures from race cond