Don't assume dataMain is a module when it is not

If the 'data-main' attribute contains a '?', it is erroneously
identified as a module name, when it will be identified as a path
upon loading. If it is not in the base directory, at that point it
will not be found.
Merge pull request #676 from rintaun/master

Allow data-main to contain URL arguments
Fix doc error
Fixes #699, require errbacks should not be called for callback errors
Fixes #721, if global onError set, then use that for require errors
Fixes jrburke/r.js#435, for packages, module config only applies to main module ID
Adding to packages config test
rev for 2.1.6