Add Custom Field Type validation
Now if you have a type like say one that implements go's sql driver Valuer see here: https://golang.org/src/database/sql/driver/types.go?s=1210:1293#L29
You can add a custom validator for any type as long as it implements the new validator.CustomTypeFunc
see the README, I added an example usage.
This was all started with a request from @johnniedoe here #133 thanks again!
Added CustomType Benchmarks
as you can see this new functionality does not slow down the pre-existing benchmarks
$ go test -cpu=4 -bench=. -benchmem=true
PASS
BenchmarkFieldSuccess-4 5000000 318 ns/op 16 B/op 1 allocs/op
BenchmarkFieldFailure-4 5000000 316 ns/op 16 B/op 1 allocs/op
BenchmarkFieldCustomTypeSuccess-4 3000000 492 ns/op 32 B/op 2 allocs/op
BenchmarkFieldCustomTypeFailure-4 2000000 843 ns/op 416 B/op 6 allocs/op
BenchmarkFieldOrTagSuccess-4 500000 2384 ns/op 20 B/op 2 allocs/op
BenchmarkFieldOrTagFailure-4 1000000 1295 ns/op 384 B/op 6 allocs/op
BenchmarkStructSimpleSuccess-4 1000000 1175 ns/op 24 B/op 3 allocs/op
BenchmarkStructSimpleFailure-4 1000000 1822 ns/op 529 B/op 11 allocs/op
BenchmarkStructSimpleCustomTypeSuccess-4 1000000 1302 ns/op 56 B/op 5 allocs/op
BenchmarkStructSimpleCustomTypeFailure-4 1000000 1847 ns/op 577 B/op 13 allocs/op
BenchmarkStructSimpleSuccessParallel-4 5000000 339 ns/op 24 B/op 3 allocs/op
BenchmarkStructSimpleFailureParallel-4 2000000 733 ns/op 529 B/op 11 allocs/op
BenchmarkStructComplexSuccess-4 200000 7104 ns/op 368 B/op 30 allocs/op
BenchmarkStructComplexFailure-4 100000 11996 ns/op 2861 B/op 72 allocs/op
BenchmarkStructComplexSuccessParallel-4 1000000 2252 ns/op 368 B/op 30 allocs/op
BenchmarkStructComplexFailureParallel-4 300000 4691 ns/op 2862 B/op 72 allocs/op