Conform to PEP8.

[lithammer]

Mostly related to lines longer than 80 characters.

$ flake8 app.py 
app.py:61:80: E501 line too long (84 characters)
app.py:89:80: E501 line too long (87 characters)
app.py:95:80: E501 line too long (106 characters)
app.py:104:80: E501 line too long (86 characters)
app.py:106:80: E501 line too long (86 characters)
app.py:108:80: E501 line too long (85 characters)
app.py:112:80: E501 line too long (89 characters)
app.py:117:80: E501 line too long (103 characters)
app.py:118:80: E501 line too long (93 characters)
app.py:123:80: E501 line too long (106 characters)
app.py:130:80: E501 line too long (98 characters)
app.py:139:80: E501 line too long (87 characters)
app.py:140:80: E501 line too long (81 characters)
app.py:145:80: E501 line too long (106 characters)
app.py:149:80: E501 line too long (86 characters)
app.py:150:80: E501 line too long (113 characters)