4.0.0 RC1

What's Changed

• statics replaced by selfs and Optional by @petrknap in #34
• Removed Optional::toNullable method by @petrknap in #38
• Template changed to covariant to allow sub-types by @petrknap in #40
• Improved PhpDocs by @petrknap in #41
• Removed unnecessary typed option examples by @petrknap in #44
• Removed type related notices by @petrknap in #45
• Optional::equals() Behavior Alignment by @petrknap in #49
• Removed TypedOptional helper by @petrknap in #51 #56
• Added referencing OptionalTest.java by @petrknap in #50
• Correct behavior of flatMap method by @petrknap in #52
• Improved map function by @petrknap in #53
• Improved filter function by @petrknap in #54
• Improved ifPresent function by @petrknap in #55
• Improved getters by @petrknap in #57

Full Changelog: v3.5.2...v4.0.0-rc1