This ticket will make some simple, safe changes to WiredTiger that will prepare for being able to compile WT in C++.

Specifically, these changes make the code largely (but not entirely) C++ compatible while maintaining C compatibility. The changes in this ticket are:

• Rename any variables called new as new is a reserved word in C++
• Make all implicit casts from void * explicit, as implicit cases from void * are not supported in C++ (see https://www.stroustrup.com/bs_faq2.html#void-ptr)

Note these are not the only changes required to make WT C++ compatible, but the changes make up 80-90% of the lines of code that would need to change, and the changes are both simple, safe, and work in both C and C++.