Permissive mime decoder for folded multibyte headers.

May handle broken emails, which contains splitted not by characters,
but by bytes multibyte strings.
Tests + some fixes for permissive header parser

Conflicts:
	src/mimemail.erl
Fixed conflict between decode-attachement and broken-folding patches.
Little more verbose permissive header decoded
Syntax error in unittests fixed

Conflicts:
	src/mimemail.erl
Re-throw original error, if permissive header decoder fails
Fix permissive headers decoder (may produce list of binaries)
Remove duplicated testcase
Merge pull request #58 from seriyps/permissive-hdrs

Permissive quoted-printable headers parser