Fixed formatting of non-ascending UIDs and indexes

Fixes issue #50
Bumped version to 0.15.0.0
code cleanup
Allow RFC822.SIZE to be 0

Fixes issue #51
Adding checks to CanTimeout in case a particular platform doesn't support setting the timeout on streams.
Update README.md

Under Installing via NuGet, instead of MailKit, MimeKit is used. I just made the correction

"The easiest way to install MimeKit is via" --> "The easiest way to install MailKit is via"
Format seq and uid ranges where min and max are identical
Bumped version to 0.16.0.0
Updated docs
Improved documentation
Added remarks to a bunch of APIs
When falling back to the default login command, call GetCredential() with "DEFAULT"
The IMAP STATUS command updates the unread count, not the first unread index
Bumped version to 0.17.0.0
Fixed the logic for throwing an exception in ImapFolder.Status() saying STATUS is not supported
Fixed ImapFolder.GetSubfolders() to set the ParentFolder for each of the subfolders.
Fixed threading of messages where the Message-Id header does not exist
Modified MessageSummary.UniqueId to be nullable

Not all IFolder.Fetch() requests will populate the UniqueId field.
code cleanup
Added a patch for issue #51 that I'm still pondering...