Merge branch 'v2'

1.7.3

~ Version number updates

Adding categories

Merge pull request spotify-web-api-java#63 from thelinmichael/eanakhl…

…-patch-1

Update pom.xml

Update pom.xml

Bumped pom versio

spotify-web-api-java#30 Updated POM version.

Bump version to 1.5.0

Update documentation for 1.4.21 and update POM

Bump to release version

Bump version and add to documentation