Check for not null on cluster when running autodiscovery

it fails during the initialization and it is never able
to set the cluster object properly remaining as null for
future runs.
Modify retryDownedHosts() to only delete hosts not in the ring if autoDiscoverHosts is true
Fix all hosts down check
Merge pull request #625 from jancona/autodiscover-and-retry

Modify retryDownedHosts() to only delete hosts not in the ring if autodiscovery is on
Merge pull request #623 from mebigfatguy/master

don't need an iterator to get the 0th item in a list.
ref hector-client/hector#600

If CQL version is set for a query, then enforce that for each execution
Merge pull request #626 from Mishail/issues-600

ref hector-client/hector#600
updating HectorTemplate with columnCounter methods.
Merge pull request #627 from awoodbury/master

adding counterColumn to spring HectorTemplate
adding types to comparator

collection, double, list, map and set types were missing. adding them to
the comparator for CQL.
Merge pull request #631 from woolfel/master

adding types to comparator
Adding javadoc to AbstractComposite explaining how it works

thanks to ed and nate for helping me figure out how AbstractComposite
works. hopefully other contributors can benefit from the javadoc and
avoid the confusion I had.
Merge pull request #632 from woolfel/master

Adding javadoc to AbstractComposite explaining how it works
added support to hector exceptions to display the host
added limit on how long client pool can be exhausted
Merge pull request #634 from shaunkalley/AddedHostToException

added support to hector exceptions to display the host
added limit on how long client pool can be exhausted
added limit on how long client pool can be exhausted
added limit on how long client pool can be exhausted
Merge branch 'ImprovedConnectionManager' of https://github.com/shaunkalley/hector into ImprovedConnectionManager