Wrote javadoc comments for the abstact sound recorder methods.

Signed-off-by: Patrick Dinklage <pdinklag@googlemail.com>
Removed the NotNull annotation.

Generally, no method parameter may be null unless explicitly allowed in the javadoc, and users should not have to bother with native null safety.

Signed-off-by: Patrick Dinklage <pdinklag@googlemail.com>
Removed the JSFML annotation.

It was poorly maintained and its information content was questionable.

Signed-off-by: Patrick Dinklage <pdinklag@googlemail.com>