Suppress warnings when application/javascript is used [0.2]

[antross]

Although text/javascript is the current best practice per discussion in #568 and noted in the HTML standard, the practical value of switching from application/javascript to text/javascript is relatively low.

More importantly this recommendation continues to cause confusion within the community as application/javascript was previously recommended by the IETF which hasn't yet updated RFC 4329 to recommend text/javascript (though an active draft exists which will make that change).

Given the conflicting state of currently published standards, the level of confusion this causes, and the limited practical benefit of using one of these mime types over the other, I propose changing hint-content-type to not raise any issues when application/javascript is used.

Note the recommended type would remain text/javascript with this change and warnings would still occur with this recommendation when any other mime-type is used (e.g. application/x-javascript).

Also note that users would still be able to override the new behavior in .hintrc to require a single type of their choosing if desired.