expose speed / high compression option

[Awendel]

I saw that the original library supports passing on a speed / compression strength option.

It's mainly affects compression speed and has the classic tradeoff between compression strength and cpu cycles spend. Decompression speed shouldn't be affected

Would maybe be nice to also add this to the library.

API could be set to the following:

compressSync(input:buffer, compressionLevel?:number, dict?:Buffer)

so that the latter are both optional but set to fastest by default (0 I beliebe)