Add CrawlConfig.get_d(), which returns a default if section or option
is missing and the default value is provided.

Use CrawlConfig.get_d() to retrieve the hsi timeout from the
configuration.
Added util.log() and tests for it. Clarifying logging to figure out
why the counts are not matching up.
Got test_log_default working
Figured out how to get filename and line number info in util.log().
Beginning to apply util.log() everywhere to make log messages easier
to trace back to particular code lines.
Use util.log() in preference to l = util.get_logger() ...
l.info(blah).
Added filename and line num to util.log() output.
Add info to cvreport(), clarify log message.
Use util.log() in preference to l = util.get_logger() ...
l.info(blah).
Typo correction.
Allow for Dimension.get_dim() to be reset to release
sqlite database and allow test dir to be deleted between tests.
Make toolframe test file executable even though it doesn't have any
executable tests yet.
Drastic simplification of method Checkable.check().
Checkable.fdparse() returns Checkable rather than a tuple.
Move all get_logger() tests from crawlTest.py to UtilTest.py.
Eliminated worries about cwd -- we no longer need to chdir back to
launch_dir in crawlTest.py.
Moved class Chdir from testhelp to util
Adding User Guide, Reference Manual links to README.
Improve error handling in toolframe.