Cleaned size checks.

Added functions: zeros, ones, trace, elementWiseProduct and
elementWiseProduct_inplace
renamed functions to be with _inplace when they replace "this".

src/Matrix.cpp

@@ -26,4 +26,5 @@ std::string _unsupported_type(const std::string& function_name)
 {
     return std::string("The type you is not supported for the function " + function_name + ".");
 }
+
 }