PLAYA-PDF 0.2.5: Bug fixes and improvements

What's Changed

• Fix various bugs in the lazy API
  • Add specialized __len__ methods to ContentObject classes
  • Clarify iteration over ContentObject
• Fix installation of playa-pdf[crypto]
• Fix attribute classes in structure tree elements
• Deprecate "user" device space to avoid confusion with user space
• Parse embedded CMaps (mostly)
• Update pdfplumber support
• Add parser for object streams and iterator over all indirect objects
  in a document

Full Changelog: v0.2.4...v0.2.5