Prefer static_cast to reinterpret_cast (#4223)

* Change reinterpret_cast -> static_cast wherever possible
* Remove more unnecessary `const_cast`s.

reinterpret_casts should be avoided for the same reason as c-style casts - they don't do any type-checking. reinterpret_cast was mainly being used for down-casting in inheritance hierarchies but static_cast works just as well while also making sure that there is actually an inheritance relationship there.

src/mbedTLS++/BlockingSslClientSocket.cpp

@@ -208,7 +208,7 @@ bool cBlockingSslClientSocket::Send(const void * a_Data, size_t a_NumBytes)
 	}
 
 	// Keep sending the data until all of it is sent:
-	const char * Data = reinterpret_cast<const char *>(a_Data);
+	const char * Data = static_cast<const char *>(a_Data);
 	size_t NumBytes = a_NumBytes;
 	for (;;)
 	{