Add module-info.java

[overheadhunter]

This adds a module-info.java and fixes #103.

Note there are two unexpected but necessary changes:

1. I had to disable builds using JDK 8. This is required for building. It does not affect the Java compatibility level, which stays at 7.
2. Due to stricter access control mechanisms in modular apps, I had to fix resource loading, which used to facilitate classloader. However, this is not recommended and breaks easily in different scenarios. See this SO post for an explanation. Please take care to review this particular change thoroughly! Edit: Reverted due to concerns mentioned below

Futhermore, it is worth pointing out that the line exports com.nulabinc.zxcvbn.matchers; inside of the module-info is only necessary due to the fact that com.nulabinc.zxcvbn.matchers.Match is exposed public API. If this class can be moved to the top-level package, this line can be removed. So from a library user's perspective, both com.nulabinc.zxcvbn.matchers.* and com.nulabinc.zxcvbn.guesses.* will be hidden.

[vvatanabe]

@overheadhunter

ResourceLoader.java solves the following problems.
#79

Without the ResourceLoader class, the above problem is likely to recur in various applications using zxcvbn4j.

[overheadhunter]

The linked issue was caused by the fact that you used to use Thread.currentThread().getContextClassLoader() instead of getClass().getClassLoader().

However, even this is not "correct", see linked StackOverflow Post. I would encourage you to just retest the new implementation, as it is the way resource loading is intended.

Edit: I believe you could even do a simple getClass().getResourceAsStream("keyboards/qwerty.txt") (note the package-relative path).

[overheadhunter]

To simplify review and not delay things further, I've re-added the ResourceLoader (added the described way of loading a resource as a first step, though). Note that the resource URL still needs to be absolute (tbh I wonder how it ever worked in the first place 🙈).

[vvatanabe]

@overheadhunter Thank you! I will prepare to release 1.6.0

[vvatanabe]

@overheadhunter I got an error in validation after publishing to sonatype. It will take some time to release it.

[vvatanabe]

@overheadhunter Now I released zxcvbn 1.6.0. Please check Java 9 Modules.

[overheadhunter]

@vvatanabe Works like a charm, thank you very much!