fix log message in RollupRunnable
use the printf format for logging
Merge pull request #316 from chinmay-gupte/chinmay/fix_log_message_of_rolluprunnable

Fix log message in RollupRunnable
Log exception in RollupRunnable
Merge pull request #317 from chinmay-gupte/chinmay/log_exception_RollupRunnable

Log exception in RollupRunnable
A tool to migrate from one cluster to another with reasonable granularity and throughput.
document the defaults.
Remove hardcoded directories from bf-migrate script.
A way to discover (and use) other cassandra nodes.
Use 5x the default TTL when no ttl is specified.
fix a typo. add some documentation.
added some documentation to the script.
Bad inputs (chunks > 4k) were causing empty server responses. throw a 400 instead.
Merge pull request #318 from gdusbabek/migration_tool

A tool to migrate data from one cluster to another
Merge pull request #319 from gdusbabek/400_on_bad_decode

Handle decoding errors more gracefully.
When there is no data, getClass (to determine the rollup type) will throw an error. Avoid that.
Do not 500 on invalid points parameter.
Validate collectionTime and TTL.
Return 400 when there are no valid metrics.
Merge pull request #320 from gdusbabek/fix_validate_points_params

Throw 400 instead of 500 when 'points' doesn't parse.