migrate to github actions

[AnderEnder]

• create initial github action: build-test, coverage, code check, doc publish
• add 3 OS: Windows, MacOs, Linux
• add 3 compiler version: stable, beta, nightly
• make code reformat
• fixe tests which were depended on OS specific new line character.
• remove travis configuration

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@0bf443c). Click here to learn what that means. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #91   +/-   ##
=========================================
  Coverage          ?   79.52%           
=========================================
  Files             ?       24           
  Lines             ?     1724           
  Branches          ?        0           
=========================================
  Hits              ?     1371           
  Misses            ?      353           
  Partials          ?        0           

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