[#5054] make pluginmap generator work again

- Fixed some assumptions that changed along the way with regards to what
  the PhpClassFile class composes and returns. Added the ability to
  aggregate namespaces as well as classes in PhpClassFile, and a getter
  for the namespaces, in order to make the pluginmap_generator work.
- Modified the pluginmap_generator to use the new methods.
Add inline comments
Fix encoding of mail headers content-type and content-type-encoding
for single-part mime mails.
Fix spacing
Fix spaces
Fix spaces
Fix spacing
Spaces fixed?
Fix identation (again) + return val
Fix eof_ending + identation change in unchanged code
Fix Validator\PhoneNumber with E.123/E.164 international numbers.
Fix CS.
Fix CS.
Remove inline comment, add comment to class property
remove package, subpackage and category

as requested by @samsonasik
added missing I18n\Validator\DateTime translations
Fixes problems highlighted by @DASPRiD and @Maks3w
- do simple in_array comparison for transfer encoding
- remove to many spaces befor equal sign
- use camelCase var names
added zendframework/zend-session as suggest dependency at Zend\ProgressBar
added zendframework/zend-cache as suggest dependency at Zend\Paginator
add regression testing for #5166 , #5197 and #5241