Handle the absence of files with the expected name more gracefully.

N.b. this patch doesn't address the hardwired assumptions about CMS-style
filenames
Point the link to igprof to a publicly visible site
Do not have debug printout if stderr is closed.

If the profiled program closes stderr stream the igprof_debug got to be disabled
to avoid garbling the output which end up reusing the closed file descriptor.
Merge pull request #23 from mkurkela/fix-close

Do not have debug printout if stderr is closed. Fixes #19.
Make the "Back to profiles index" use an index.{htm,html} file if present
in the directory containing the .sql3 files