urlmon: Implement FindMimeFromData

[Kevin Koltzau]

Here is an implementation of FindMimeFromData, based off of MSDN
http://msdn.microsoft.com/workshop/networking/moniker/overview/appendix_a.as...

There is lots of debate on the 'net regarding this "feature" in IE, most of it suggesting
this is a bad idea..

One possible change that would work more "standards compliant" rather then "Windows like"
would be to return the proposed MIME type unchanged if one is given, otherwise go through
the detection methods..let me know if that would be a preferred solution

Changelog
    Implement FindMimeFromData