Item12446: Better compatibility with version

Use $version::LAX regex to determine if the version strings are
supported by CPAN:version.  If so, compare using the CPAN module.

There are a couple of changes:

 - Underscore is not replaced within the version string, it has special
   significance for CPAN:version comparisons for alpha releases.

 - Strings compared with and without 'v' prefixes are changed.  Without
   the leading 'v', version normalizes so 1.2 becomes 1.200.   With
   cpan:version,  1.2 is not the same as v1.2.

 - Simple decimal versions are compared as real decimal numbers.  So
   1.13 is NOT newer than 1.2.

Updated unit test to validate that Dependency.pm results agrees with
CPAN:version results for version comparisons.

git-svn-id: http://svn.foswiki.org/trunk@16672 0b4bb1d4-4e5a-0410-9cc4-b2b747904278