Make API structs/functions/enums public
Uncomment import for unit tests
Correctly handle boxed values

This was causing errors in old versions of the Rust compiler, but encoding the
unboxed versions makes more sense anyway.
Add add_page method
Add add_entry method
Add parameters to Log::new

Browser/comment are most likely to get set on object creation, so they get put
in the constructor.

Not 100% sure about the comment, but browser definitely.
Introduce constructor for Browser
Release version 0.0.2