def of "equals" fn in readme and typo

[salamynder]

1. Typo at mithril example: closing paren ")" missing.
2. At the same place there is a "equals" fn of which I cannot find a definition. Maybe "equalsTo" from the validatex package is meant?

[ludbek]

Thanx for reporting :). https://github.com/ludbek/powerform/commit/054c88d259eb62b791925ce58f4982315b9d32b8