Bumping version to 0.15.0

Updating install links for version 0.14.0

Bumping to version 0.13.0

Merge branch 'master' of https://github.com/dbcli/mssql-cli

Removing redundant method in connection service. (dbcli#169)

* Removing redundant method in connection service.

* Updating mssqlcliclient to surface error messages to it's callers.

* Removed copyright statement in test and flake8 format.

* Converting output of stack trace to be logged instead.

Bumping version for release 0.9.0