generate const values for enumerations

[SoMuchForSubtlety]

This partly addresses #17 by generating const declarations for enums. I also fixed some linter errors.

Maybe we should omit numerical enums since they don't have useful names?

// May be one of 0.9, 0.333333333, 0.0
type FloatType float64

const (
	FloatType_0_9         FloatType = 0.9
	FloatType_0_333333333 FloatType = 0.333333333
	FloatType_0_0         FloatType = 0.0
)

// May be one of 1, 2, 3
type IntType int

const (
	IntType_1 IntType = 1
	IntType_2 IntType = 2
	IntType_3 IntType = 3
)

It would probably also make sense to gate this behind a config flag, what do you think?

[TAR5]

Great feature!