[cecilia] Check and fix assumptions on the sizes of pointers and integers...
Cecilia-generated code, Cecilia runtime code and other libraries should be made free of assumptions on the sizes of integer and pointer types, if they aren't already free of such assumptions.
In my tests:
- the whole Cecilia test suite and all three Cecilia examples are OK on 64-bit Linux;
- HelloWorld and Cloneable work properly on a platform where sizeof(int) == 2.