add new property MetricsCollection

Signed-off-by: Stephen Gran <stephen.gran@piksel.com>
Instead of just list for MetricsCollection, use [MetricsCollection]
Merge branch 'sgran-asg_metrics_collection'
Patching Users class to use basestring or Ref type for Groups and not Groups type.
See: https://github.com/cloudtools/troposphere/issues/78
Merge branch 'ryno75-master'
Added support for Kinesis
Merge branch 'ganguera-master'
Update recent changes
Merge remote-tracking branch 'upstream/master'
Added support for Redshift