Refactor repr, str/print, summary, etc

[jacobpennington]

New pretty-print hierarchy to reduce the amount of text output by default
(example for Model, but similar for Layer, Phi etc):

repr - Model(layers=3, parameters=102, name='LN') # one liners
str - Model(...)

WeightChannels( ...): total parameters: 54
FIR(...) total parameters: 45

etc, similar to current repr. Medium length option.

.verbose() - put current str/print here, full output with all parameter values and attributes