Merge pull request #387 from Chubercik/ambiguity_fix

Fix ambiguous calls to `safe_shift_left()` in `basisu_containers.h`
diff --git a/transcoder/basisu_containers.h b/transcoder/basisu_containers.h
index 03fae33..7fff4c2 100644
--- a/transcoder/basisu_containers.h
+++ b/transcoder/basisu_containers.h
@@ -3349,7 +3349,7 @@
 
 		inline size_t hash_key(const Key& k) const
 		{
-			assert((safe_shift_left(1ULL, (SIZE_T_BITS - m_hash_shift))) == m_values.size());
+			assert((safe_shift_left(static_cast<uint64_t>(1), (SIZE_T_BITS - m_hash_shift))) == m_values.size());
 
 			// Fibonacci hashing
 			if (SIZE_T_BITS == 32)
@@ -3433,7 +3433,7 @@
 				return false;
 
 			new_map.m_hash_shift = SIZE_T_BITS - helpers::floor_log2i((uint64_t)new_hash_size);
-			assert(new_hash_size == safe_shift_left(1ULL, SIZE_T_BITS - new_map.m_hash_shift));
+			assert(new_hash_size == safe_shift_left(static_cast<uint64_t>(1), SIZE_T_BITS - new_map.m_hash_shift));
 
 			new_map.m_grow_threshold = std::numeric_limits<size_t>::max();