edit gemspec
add string input
add tests for max and min for languages
Merge branch 'feature/string_input' into develop

* feature/string_input:
  add tests for max and min for languages
  add string input
fix string input
add more tests
add interfaces to readme
update version
Merge branch 'release/0.3.5' into develop

* release/0.3.5:
  update version
  add interfaces to readme