Coerce query values of where clause based on property types

filter.where from HTTP query strings are coerced based on the format matching. For example, 
filter[where][a]=1 is parsed as {filter: {where: {a: 1}} no matter what type for property 'a' is.

Please see the discussion at:
https://groups.google.com/forum/#!topic/loopbackjs/0EX2T-CxVlU