Added stricter templates to type-infering functions

EventQueue::event is now defined for the following overloads:
- event(R (*)(A...),                                       C...)
- event(F,                                                 C...)
- event(const F,                                           C...)
- event(volatile F,                                        C...)
- event(const volatile F,                                  C...)
- event(T *,                R (T::*)(A...),                C...)
- event(const T *,          R (T::*)(A...) const,          C...)
- event(volatile T *,       R (T::*)(A...) volatile,       C...)
- event(const volatile T *, R (T::*)(A...) const volatile, C...)

This insures cleaner error messages when invalid types are used.

It should be noted that different types are used for the infered
function parameters and the arguments supplied to event, this is
important for inducing implicit casts.

Otherwise, deceptively confusing bugs can occur:

    void doit(unsigned value);
    queue.event(doit, 1); // Error - 1 is signed without implicit casts

Author: geky