link: Add uri property

Increases symmetry with Track(uri=...), etc
link: Add repr() with uri
track: Add repr() with uri
album: Add repr() with uri
artist: Add repr() with uri
user: Add repr() with uri
playlist: Add repr() with uri
image: Add repr() with uri
search: Add repr() with uri
sequence: Add repr() using list format
search: Add playlist property to search playlist
search: Add image property to search playlist
search: Set search_type default for all __init__ paths
search: Rename SearchResult* to Search*
search: Doc new SearchPlaylist properties