Set up validation to reshape the input

[tms-bananaquit]

• This'll probably come up again down the line unless validation copies and reshapes the data.
• In the case of the streaming detectors, it's not much additional memory. In the case of the batch detectors, the reference data needs to be a static copy whenever it's set.
• The validation should probably be moved into update and set_reference in the child classes, because return values from super().* seem unintuitive.
• Double-check that the concept drift detectors expecting floats/ints behave when arrays are passed

On the other hand, making copies of huge arrays is a waste except when they're being used in set_reference. Going to leave this as-is for now, unless something comes up down the line that motivates doing this copying universally.

[tms-bananaquit]

Went through with this in #103 .