* deprecate Python2.7.
So we can use latest version of prompt-toolit.
Relate: https://github.com/dbcli/pgcli/pull/1149
* black format, remove 2.7 support.
* using version py35 for black.
* Revert "black format, remove 2.7 support."
This reverts commit 4b6d0496cc.
* deprecated py27 using black.
* remove 2.7 from travis.
* update setup.py: delete python 2.7 support.
* README.rst: tidy up redundant instructions
Remove the README section which detailed how to force `psycopg2` 2.7 dependency installation from source rather than binary.
`psycopg2` 2.7 would automatically favour installation from binary. A bug affecting some users made it desirable to have the option to install from source instead. The README detailed how to do this using pip's `--no-binary` option (nice!).
`psycopg2` 2.8 has now split the binary and source dependencies into different packages with different names (source: [psycopg2 docs](http://initd.org/psycopg/docs/install.html#change-in-binary-packages-between-psycopg-2-7-and-2-8)) which makes the `--no-binary` instructions redundant. To specify source/binary you now need to explicitly specify the desired package.
As of #1060, installing `pgcli` from pip will result in the installation of `psycopg2` 2.8 from source.
* README: additional instructions for psycopg2 2.7 users
Anyone limited to psycopg2 2.7 may still encounter some known issues when installing from binary.
Add a link to the README to acknowledge this, and help those users install it from source.
* Update changelog.rst
* Update AUTHORS
* Update changelog
Click 3 is no more. I'd suggest linking to the root of the Click website and letting it redirect to the current stable version since they seem to be removing pages for the older versions.
