Change line endings in Base64.java to be native.

Basically changes Windows CRLF to UNIX LF, this is so platforms which
do line ending translation (i.e., msysgit) can handle Base64.java
correctly, instead of thinking it's constantly changed, and blocking
rebasing. Fixes issue 4056.

Change-Id: Iefbb95c3484c4c7fe9f8a24afd9cafdce3e65dd4
Reviewed-on: http://gerrit.dmdirc.com/1166
Reviewed-by: Gregory Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>