Updated build to use Gradle instead of Maven

[techbrew-mc]

I also recommend renaming the repo to "twitch-api-wrapper" to keep consistent with the artifact name.

These changes work nicely with jitpack.io as well: https://jitpack.io/#techbrew-mc/twitch-api-wrapper/0.3.1
(That makes it easy to integrate into other projects without having your releases in Maven Central.)

[Gikkman]

JitPack can be used with any GitHub release, given that it is configured correctly, so it is not necessary to move to Gradle for that reason alone.

I guess acceptance this pull request will depend on whether @urgrue uses Gradle in his development setup or not. Did you see #20 ?

[techbrew-mc]

I didn't see #20, but I did see the roadmap mention of Gradle.

Moreover, the existing maven build doesn't work in jitpack, so perhaps fixing that would be the better compromise:

https://jitpack.io/com/github/urgrue/Java-Twitch-Api-Wrapper/0.3/build.log

[Gikkman]

You're right, it doesn't work with JitPack... I really thought it did... That is definitely something we should strive to fix then.

[SamboyCoding]

I've fixed the maven build in #27, just waiting on approval.