Fixes tedivm/Fetch#43 by creating a name for nameless attached emails, allowing them to be seen as attachments rather than merged into the parent email.
Removed error_log statements I mistakenly left in while debugging; corrected spelling error
Abstracted messageBody processing from processStructure and enabled extraction of attached .eml file's subject line for use as the filename in addAttachment, with 'email.eml' as fallback.
Forgot to document the new method.
Some more changes to support pulling the Subject line from a .eml and using it as the filename.
Fixed issue with the Subject line parsing regex, which would cause it to succeed on malformed .eml files, but fail on correctly-formatted .eml files.
syntax error
Fixing bugs reported by scrutinizer ('The class Fetch\Exception does not exist' and 'It seems like  can also be type ; however,  does only seem to accept , maybe add an additional type check?').
Converted tabs to 4 spaces. Moved opening braces to the line after the function declaration.
Ran PHP-CS-Fixer.
Subject-to-Filename parsing got confused by DKIM-Signature section of signed email. Changed regex to be more specific and resilient.
My IDE lost its tabs --> spaces setting, and ended up putting tabs in again. Replaced all tabs with spaces.
Made some changes to the processing of email contents and encoded Subject lines.
Simplified encoded Subject-line processing into filename. Skip processing on message/rfc822 attachments in order to avoid mangling the file.
The code was still causing attached HTML files to be inlined. Now anything with a disposition of 'attachment' will be added to the  array rather than inlined.
Merge remote-tracking branch 'adriantp/issue43' into stream-save

Resolves #43

Conflicts:
	src/Fetch/Message.php
	src/Fetch/Server.php
	tests/bootstrap.php
Add rfc822 support to Attachment::saveAs()