v0.5.0 - Simplify Command Interface

Improve consistency in interface, especially between book and review commands. Adding same search and filter commands to both. Simplifies by removing "show" and treats as default action.

libro book - show recent books added
libro review - show recent reviews added

libro book ID - show book details for book ID
libro review ID - show review details for review ID

Improve consistency across all actions, book and review support same flags

libro book --author NAME - show books matching author NAME
libro book --year YEAR - show books published in YEAR
libro book --title TITLE - show books matching title TITLE

libro review --author NAME - show reviews matching author NAME
libro review --year YEAR - show reviews entered in YEAR
libro review --title TITLE - show reviews matching book title TITLE

See #18 for full details