fix(kff.define): typo in factory var name
refctor(kff.App): middlewares array should be passed to front controller service config so that it can contain DI references to other services
feat(kff.CallBinder): a new binder that calls a method of a model with any arguments. The attribute part of model path must be a valid model methos. Arguments can be plain strings or models from the current scope (prefixed with @ char).
feat(kff.Binder): add method kff.Binder#convertValueType to do implicit conversion of basic data types from string. Used to process kff.CallBinder arguments.

Conversions are as follows:
"null" => null
"true" => true
"false" => false
"42" => 42 (convert number in string to number)
feat(kff.ClassBinder, kff.EventBinder): parse values in bindings using  kff.Binder#convertValueType method to do basic type conversions.
refactor(kff.ClassBinder): parse values in bindings only once on init.
feat(kff.InsertBinder): parse values in bindings using  kff.Binder#convertValueType method to do basic type conversions.
fix(kff.InsertBinder): destroy InsertBinder properly in force mode so that it works when nested in another InsertBinder
feat(kff.IfBinder, kff.IfNotBinder): create two new binders ('if' and 'ifnot') that work like the 'insert' binder with a new clearer syntax

Both binders work with implicit 'force' mode enabled. It cannot be disabled.

* 'if' binder works like 'insert' binder
* 'ifnot' binder works like 'insert' binder with 'ne' parameter turned on
fix(kff.ClassBinder): check for existence of 'equalsTo' parameter instead of its truthy value