Added the `--automatic-namespaces` option

Added an --automatic-namespaces option to automatically select source and destination prefixes and delimiters for the migrate and mirror commands.

Fix bug in message length calculation

This release fixes a bug in serialization where message lengths were calculated in Unicode codepoints, not in bytes.

Any folder backup made using version 11.1.0 and may contain non-ASCII characters should be redone from scratch.

Improve Handling of Badly Encoded Messages

We now force the body encoding to UTF-8

With badly encoded message, an error was being thrown:

    Encoding::CompatibilityError: incompatible character encodings: UTF-8
    and ASCII-8BIT

The problem occurred when:

1. The server returned a badly encoded email message,
2. there were non-ASCII characters in the 'From' line
3. there were non-ASCII characters in other parts of the message.

In this case, the 'mail' gem force encoded the 'From' line as UTF-8,
but the body was still be "ASCII-8BIT". Without non-ASCII characters,
the 'From' line got coerced to the same encoding as the body,
but when both parts had non-ASCII characters, the error was thrown.

Now, we force the body to UTF-8 before uniting it tieh the 'From' line.

Fix Transaction Rollback

Fix an erroneous call in transaction rollback during backup

Download Strategies

The default downloading strategy now delays writing metadata until
the whole folder has been downloaded. For very large mailboxes
(e.g. with >100k messages) this results in an approximately
30x speedup in download times. The strategy can be chosen in the setup
program, under 'global options';

Secondly, when any account backup fails, the program now exits with a non-zero
exit code.

Bugfix for missing Imap namespace

v10.0.1

Version 10.0.1

Improve Thunderbird Exports

From the CHANGELOG:

• Improved logging output for Thunderbird exports,
• Stopped exports when the destination profile is not yet ready.

Improve help for subcommand methods

Previously, when help was requested on a subcommand method, the output was of listing all subcommand methods.
Now, the output is now the help for that specific method.

By default, commands like imap-backup help foo bar are handled by listing all foo methods, whereas the user probably wants the detailed help for the bar method.

By moving any initial "help" argument to after any subcommand, we get help for the requested subcommand method.

Handle Errors on Folder Creation

v9.3.0

Version 9.3.0

Handle invalid file name characters in folder names

This release handles invalid file name characters (specifically ':') in folder names.

Invalid names are encoded to hex codes.

As the encoding uses '%' and ';' to delimit encoded hex values, these characters themselves are now considered 'invalid' for serialized folder names and are encoded. Existing backed up folders with these characters in their names (or paths) will be re-downloaded.