Improve project template

[victorsndvg]

• Add .travis.yml file to trigger automated CI in github
• Add docs initial scheme
• improve .gitignore file
• Add badges to README.md
• Check more gcc versions

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@ed2a40c). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master       #1   +/-   ##
=========================================
  Coverage          ?   88.23%           
=========================================
  Files             ?        4           
  Lines             ?       51           
  Branches          ?        0           
=========================================
  Hits              ?       45           
  Misses            ?        6           
  Partials          ?        0

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