Support more commonly-used null-safe property navigation syntax

Currently in order to make a null safe property navigation, the syntax is ?nullSafeProperty.property
For example, foo.?bar.p
means foo.bar == null ? null : foo.bar.p

There are many scripting language adopting a different syntax: ?.
The above example becomes: foo.bar?.p
which is more intuitive because
1) the null-checking is put together with the corresponding navigation (.) . Existing syntax of MVEL is a bit misleading because .? seems to come together, but in fact the latter ? affects the next navigation.
2) The syntax (?.) can be easily understand by "reading" as : is not null then navigate (.)

It seems to me both syntax can coexists in order to maintain backward compatibility.

For example
foo.?bar.apple?.?boy.car

seems interpretable.