Upgrade dependencies

This PR updates prompt_toolkit (with code) to version 2, and bumps requests depedency version.

idk

• Add playing song to toolbar
• Update prompt colors
• Better error handling for the auth

Authorization

Must authorize in order to search for songs

Commander

The commander enriches the search with commands which enables us to perform different operations without leaving the search field.

Banana error

• Simplify search string
• Updated short keys
• Large parts of curses rewritten
• Dbus interface factory
• Get current playing song with pytify -c
• Add meta data dbus class
• Absolute imports
• Unicode literals
• Add application name, version and repo to the cli
• Update license

Tab completion

• Tab completion
• Minor refactoring

New and shiny Pytify

• Search history
• Auto suggest
• Refactor
• No Python 2 support

Python 3.5 support

Supports both python 2 and 3-3.5