Merge branch 'release/0.2.18' into develop

* release/0.2.18:
  update version
refactor
fix bigtest
add errors codes
add support_negative method
remove function
refactoring tests
add bignumber test for English
add new tests
Merge branch 'feature/up_coverage' into develop

* feature/up_coverage:
  add new tests
  add bignumber test for English
  refactoring tests
  remove function
  add support_negative method
update version
Merge branch 'release/0.2.19'

* release/0.2.19:
  update version
  add new tests
  add bignumber test for English
  refactoring tests
  remove function
  add support_negative method
  add errors codes
  fix bigtest
  refactor