AttributeGenerator.pm: Singlequote instead of doublequote
DocumentGenerator.pm: Declare #ABSTRACT in generated modules
Replace Path::Class with Path::Tiny
Shut up perl critic, SHUT, UP. BLOODY PEASANT
Update changes and README
v0.1.3

 [!Noteworthy Changes]
 - Moved from Path::Class to Path::Tiny
 - Emit generated attributes with single-quote keys.
 - Add a #ABSTRACT declaration to all generated files

 [Dependencies::New / runtime requires]
 - Path::Tiny

 [Dependencies::Removed / runtime requires]
 - Path::Class::Dir