Coercion for Decimal doesn't work as expected

[LukasRychtecky]

Hi,
thank you for this library.

When I get a number from e.g. Ring request I'd like to coerce it to Big Decimal.

(s/def ::amount (s/and decimal? pos?))
(sc/coerce ::amount "") ;; throws java.lang.ArrayIndexOutOfBoundsException
;; but I expect to get "", because the value is not possible to coerce

(sc/coerce ::amount 1) ;; it returns 1
;; but I expect to get 1M, because the value is Long 

So I suggest to:

1. parse-decimal function should not care if x is string or not.
2. parse-decimal should be wrapped in try-catch.

What do you think about it?

[wilkerlucio]

hello @LukasRychtecky :)

I think it makes sense, can you like to send a PR with the described changes?

[LukasRychtecky]

@wilkerlucio Fine, I will create a PR ;)