new release

[slayoo]

let's get an official release out shortly. Once that release is out, then we go forward with "breaking" changes, for example:

• Stop supporting Autotools
• Stop supporting pre-C++11

Originally posted by @citibeth in https://github.com/blitzpp/blitz/pull/136#issuecomment-491288456

[slayoo]

@citibeth, @lutorm, @papadop Any objections to:

• bump version number
• commit regenerated configure
• make a github release
• clean the repo from autoconf stuff (incl. configure)

[slayoo]

No objections. Done. https://github.com/blitzpp/blitz/releases/tag/1.0.2