Propagate nans in binary ops (#579)

* propagate nans in binary ops

* handle empty matmul

* cpu minimum/maximum propagate nan

* benchmark maximum

* add min as well

* throw on negative indices with full

* verbose on linux

* fix matmul for zero K

tests/creations_tests.cpp

@@ -151,6 +151,12 @@ TEST_CASE("test astype") {
 }
 
 TEST_CASE("test full") {
+  // Check throws on bad shape
+  {
+    CHECK_THROWS(full({-5, 0}, 0));
+    CHECK_THROWS(full({0, -5}, 0));
+  }
+
   // Check full works for different types
   {
     auto x = full({}, 0);