Add abortCall method
"abortCall" method unit test
Fixed #51: domino.module inheritance facultative

From now one, it is no more necessary to make every modules inheritate the domino.module class, since their constructors are actually called on new domino.module instances.
Also added a unit test checking that both old and new versions still work.
NPM modules versions up to date

Just refreshed the different development NPM dependencies.
Removed some rules (6 and 13) from the last version of the linter.
Fixed some lint issues in domino.js related to the jslint update.
Fixed #49: Added domino.struct.existing

"domino.struct.existing()" returns a clone of the custom structures object.
"domino.struct.existing(key)" returns the related structure, or undefined if it does not exists.
Also added unit tests.
release v1.3.4

Updated NPM dependencies to their latest versions
Fixed #49: Added domino.struct.existing
Fixed #51: domino.module inheritance facultative
Fixed #50 and #52 (thanks [ZorGleH](https://github.com/ZorGleH)!)