Fix comment skipping code.

Didn't work at all, amazingly enough - it was using regexp
style instead of globbing. Also broke in the face of blank lines.
jvm_opts files can now contain lines starting a # and blank lines,
but lines with a non-initial # are options.

Used new testing abilities to include a test. Whoo.
Merge pull request #69 from paulp/comments

Fix comment skipping code.