Alpha release for test usage only (v0.2.19-alpha)

With polyphony support, one oscillator, amp envelope and filter envelope support.
Only for testing usage.

Version of this plugin will be 1.0.0, this is not a bug, just because i have not change it 😄

both are debug build.

支持复音，有一个osc，支持AmpEnvelope和FilterEnvelope。
仅供测试。

宿主可能会告诉你插件版本是1.0.0，因为默认这个值，懒得改（不影响测试）😆

均带调试符号。