Add new dynamic array syntax.

sourcepawn/compiler/tests/fail-dynamic-array-bad-type.sp

@@ -0,0 +1,4 @@
+public main()
+{
+  int[] x = new float[3];
+}

sourcepawn/compiler/tests/fail-dynamic-array-bad-type.txt

@@ -0,0 +1 @@
+(3) : error 164: allocated array type 'float' doesn't match original type 'int'

sourcepawn/compiler/tests/ok-new-dynamic-array-syntax.sp

@@ -0,0 +1,10 @@
+native printnum(num);
+
+public main()
+{
+  new x = 4;
+  new y = 8;
+  int[][] v = new int[4][8];
+  v[2][3] = 9;
+  printnum(v[2][3]);
+}