[kutil] Add kutil::map hash map

Added the kutil::map collection, an open addressing, robinhood hash map
with backwards shift deletes. Also added hash.h with templated
implementations of the FNV-1a 64 bit hash function, and pulled the log2
function out of the heap_allocator code into the new util.h.

src/tests/map.cpp

@@ -0,0 +1,63 @@
+#include "kutil/map.h"
+#include "catch.hpp"
+
+TEST_CASE( "map insertion", "[containers] [vector]" )
+{
+	using clock = std::chrono::system_clock;
+	unsigned seed = clock::now().time_since_epoch().count();
+	std::default_random_engine rng {seed};
+	std::uniform_int_distribution<int> distrib {0, 10000};
+
+
+	size_t sizes[] = {1, 2, 3, 5, 100};
+	for (size_t s : sizes) {
+		kutil::map<int, int> v;
+		std::vector<int> r;
+
+		for (int i = 0; i < s; ++i) {
+			int j = distrib(rng);
+			r.push_back(j);
+			v.insert(j, j);
+		}
+
+		for (int i : r) {
+			int *p = v.find(i);
+			CAPTURE( i );
+			CHECK( p );
+			CHECK( *p == i );
+		}
+	}
+}
+
+TEST_CASE( "map deletion", "[containers] [vector]" )
+{
+	using clock = std::chrono::system_clock;
+	unsigned seed = clock::now().time_since_epoch().count();
+	std::default_random_engine rng {seed};
+	std::uniform_int_distribution<int> distrib {0, 10000};
+
+	size_t sizes[] = {1, 2, 3, 5, 100};
+	for (size_t s : sizes) {
+		kutil::map<int, int> v;
+		std::vector<int> r;
+
+		for (int i = 0; i < s; ++i) {
+			int j = distrib(rng);
+			r.push_back(j);
+			v.insert(j, j);
+		}
+
+		for (int i = 0; i < s; i += 2) {
+			v.erase(r[i]);
+		}
+
+		for (int i = 0; i < s; ++i) {
+			int *p = v.find(r[i]);
+			CAPTURE( i );
+			if ( i%2 )
+				CHECK( p );
+			else
+				CHECK( !p );
+		}
+	}
+}