Update forms.go

If a field is required, we need to have a value for it.
Add boolean fields support add max and min len in regex
fix switch issue, add check on multiple values
Holding #001, fix regex_test, fix little bug in form
Write tests (Close #001)
Update readme
Update README.md
Add json field
[RDY]
Merge branch 'master' of https://github.com/MartinBrugnara/goforms

Conflicts:
	README.md
Merge pull request #3 from MartinBrugnara/master

Add Boolean and JSON field support.