Release v0.3.0

What's Changed

• docs(README): Adding logo by @simonnix in #6
• chore(codecov): Adding codecov by @simonnix in #7
• chore(coverage): Add test to complete coverage by @simonnix in #8
• docs: limit line width in documentation by @simonnix in #9
• refactor: Add type "SetValue" to Optional by @simonnix in #10
• feat(util): add MapEntry type by @simonnix in #11
• feat(stream): Add implementation of Java 8 Stream by @simonnix in #12

Full Changelog: v0.2.2...v0.3.0