Add readme

[e-ave]

This project is in dire need of an example in the readme. Like for example what does “to” and “from” argument do? I cannot for the life of me figure out what to put for these two arguments. Then looking at the code just adds fuel to the confusion.
Why isn’t java -jar tinyremapper.jar client.jar mapped.jar mappings.match enough? What is the point of “toM” and “fromM”?

[Juuxel]

from and to are the mapping namespaces (e.g. "intermediary" or "named") in a tiny-format mapping file, which can have any number of namespaces (at least 2, see #9).

To my knowledge you can't use .match files directly but Matcher can output .tiny files via the "Save Mappings" option as well.