#640 TMailer does not work if the application bitness differs from Outlook

[Ognyan Chernokozhev]

If a 32-bit application is trying to use TMailer class to send emails, but the installed Outlook is 64-bit (or vice-versa), the call fails with error 2147500037 - The specified procedure could not be found.

This can be demonstrated in the RichEdit example by using the Send menu item.

Maybe TMailer::IsMAPIAvailable should check is the application and Outlook bitness match and return false otherwise.

[Ognyan Chernokozhev]

Note: under the hood TMailer uses the MAPISendDocuments function which is marked as "The use of this function is discouraged. It may be altered or unavailable in subsequent versions of Windows."

With the pending deprecation of classic Outlook and move to New Outlook, which does not support MAPI, this class may no longer be depended on in the future.

[Ognyan Chernokozhev]

Note: The fix can be backported to the 7 and 6.44 branches, but it may bot be worth it if noone is actually using the TMailer code - and if they do, they should have already implemented their own checks for MAPI availability.