Multiline string support

[fernandoacorreia]

Trying to use multiline strings in a feature gives INDENT errors. For instance, trying to run cucumis on https://github.com/cucumber/cucumber-features/blob/master/core.feature (after converting spaces to tabs) gives this message:

Error caught:
    name: Error
    message: Unexpected token "INDENT" at line 17
      Error: Unexpected token "INDENT" at line 17
          at Object.checkToken (/home/fernando/Downloads/cucumis/deps/kyuri/lib/kyuri/parser.js:407:13)
          at Object.parse (/home/fernando/Downloads/cucumis/deps/kyuri/lib/kyuri/parser.js:392:14)
          at Object.parse (/home/fernando/Downloads/cucumis/deps/kyuri/lib/kyuri/core.js:52:17)
          at runFeature (/home/fernando/Downloads/cucumis/bin/cucumis.js:224:20)
          at next (/home/fernando/Downloads/cucumis/bin/cucumis.js:176:5)
          at /home/fernando/Downloads/cucumis/bin/cucumis.js:182:4
          at next (/home/fernando/Downloads/cucumis/bin/cucumis.js:217:4)
          at notifyListeners (/home/fernando/Downloads/cucumis/bin/cucumis.js:219:3)
          at runFeatures (/home/fernando/Downloads/cucumis/bin/cucumis.js:173:2)
          at Object.<anonymous> (/home/fernando/Downloads/cucumis/bin/cucumis.js:143:1)