Show attachment allowed file types and max file size

[web2works]

Add a simple option to the admin settings for attachments, if set it will show the extra information in the form. This would be very useful information to the user e.g: instead of guessing what the file size is.

Also I have found that when some users reply via email we sometimes get a large amount blank lines, would it be possible to automatically remove these when they reply via email?

E.g this is the changes I have made and would need modifying slghtly:

Allowed File Types: <b><?php echo str_replace("."," ",$cfg->getAllowedFileTypes()); ?></b>
Max File Size: <b><?php echo bytesToSize($cfg->getMaxFileSize()); ?></b>

[ntozier]

Good feedback. I like it at least.