Release x.y.z

[pinkforest]

Tracking issue for the next release.

Follow-up from:

• https://github.com/phsym/prettytable-rs/issues/147

This needs to be handled:

• #140
• https://github.com/phsym/prettytable-rs/issues/117

If luck maybe these:

• #119
• #150
• https://github.com/phsym/prettytable-rs/pull/118

Keen to move color to as feature that includes termcolor optionally.

Anything else ? Keen to get 1.0.0 out too at some stage.

If someone has time to work on PR's that would be most apperciated - e.g. for termcolor / fixing panics