Remove extra stuff from target

[bootstraponline]

A bunch of files in https://github.com/appium/java-client/tree/master/target don't need to be checked into version control (for example the .class files).

[Jonahss]

thanks, I'll clean it up

[Jonahss]

It's ok to keep the java docs and compiled jars, right?

[bootstraponline]

It's ok to keep the java docs and compiled jars, right?

👍