Core.use.sharedptr

[roccoarpa]

@edoardolombardi. Pull works for both serial and MPI versions, all test and examples seems to work.

Here a list a check that still need to be performed.

• [x] testing IOOFOAM with its relative example

• [x] testing parallel version(with relative examples) with np > 2

• [x] A quick review of code for propagators and parallel module is advisible, just to be careful.

The most important modifications for shared pointer are in 82537ec04fe51fd5e6d7c6382390654cdc4a869b

[edoardolombardi]

Updated with some fixes. Check verified.