#445 basic support for alternative npm registry
split lines for readability, jeez
#445 don't fail when no registry is set
add support for alternative CPAN servers
Merge pull request #524 from hatt/source-select

Various source selectors
Fix gem command conflict with specific_install

When specific_install is installed, calling "gem spec" is ambiguous and
fails.  Call it with the full name "gem specification" instead to avoid
that.
Merge pull request #533 from petere/gem-spec-conflict

Fix gem command conflict with specific_install