Use simple array for Pawns Connected bonus #2061

Simplification which removes the pawns connected array.
Instead of storing the values in an array, the values are
calculated real-time. This is about 1.6% faster on my machines.

Performance:
master ave nps: 159,248,672
patch ave nps: 161,905,592

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 20363 W: 4579 L: 4455 D: 11329
http://tests.stockfishchess.org/tests/view/5c9925ba0ebc5925cfff79a6

Non functional change.

src/main.cpp

@@ -42,7 +42,6 @@ int main(int argc, char* argv[]) {
   Position::init();
   Bitbases::init();
   Search::init();
-  Pawns::init();
   Threads.set(Options["Threads"]);
   Search::clear(); // After threads are up