https://issues.apache.org/bugzilla/show_bug.cgi?id=54707
Review of r1457303:
1) Correct comments.
2) In readLhex(..):
Document lowercase conversion. It was documented before r1457303 and
I think it is in line with support for incorrect values implemented
in response to BZ 54707.
Convert digits to lowercase on the fly, instead of relying on
String.toLowerCase() call. This should generate less garbage for GC.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1457362 13f79535-47bb-0310-9956-ffa450edef68