Fixed the pom.xml to eliminate redundant dependencies.

When running in Eclipse, the various javax.servlet jars were
colliding with each other causing problems. The conflicts were a result
of the javax.servlet jars from hadoop, hbase and dropwizard. Removing the
ones from Hadoop and HBase and keeping the ones in DropWizard seems to fix
the problem. Just something to be aware of if we bring in more hadoop related
dependencies.

Reviewed by: shashir
KIJI-772. KIJI-770. List instances and list tables.

When GET /v1/instances/ is called, all accessible instances are listed.
Similarly when GET /v1/instances/<instance>/tables is called, all
tables on the available instances are listed. Added ResourceConstants
class.
Use the root pom. Override the guava version so that the dropwizard
guava version wins.
KIJI-something
KIJI-770. Informative lists.
Checkstyle and general cleanup