Color features and lots of bug fixes

New features:

• Any valid matplotlib color string is now a valid color to use in py5 (if matplotlib is installed)
• New hex_color() method
• New select_folder(), select_input(), and select_output() methods
• Upgraded random_choice() method
• New np_random property
• New g property
• New next_page() method for the PDF renderer
• Proper object equality

See the blog post for more information about this release.

Bug fixes:

• # 111
• # 109
• # 107
• # 105
• # 99
• # 91
• # 90
• # 89
• # 87
• # 86
• # 82
• # 76