Lock tools version

Merge pull request #162 from citusdata/ozgune-patch-1

Minor update to point to our Slack channel

Merge pull request #160 from citusdata/documentation/fix_parallel_command

Merge branch 'develop' into documentation/fix_parallel_command

Merge pull request #161 from citusdata/deprecation

Code review fixes

Emphasize feature completeness of extension

Add pg_shard deprecation message suggesting Citus extension

Fix erroneous shell command

Merge pull request #159 from citusdata/feature-use_citus_tools

Switch to Citus Data-owned Travis scripts

Merge pull request #158 from citusdata/feature-95_final_compat

Restore 9.5 compatibility

Merge branch 'release-1.2.3' into develop