Fix mingw warnings on recent changes to Matrix4x4.

Moving the definition of the matrix Multiply4x4 method after the
definition of the array Multiply4x4 method should fix the warning below.

Warning:
http://open.cdash.org/viewBuildError.php?type=1&onlydeltap&buildid=3034528

Ref:
http://stackoverflow.com/questions/11546403/importing-inline-functions-in-mingw

Change-Id: If3f58545b81d6df030a788f4ca8e60f08dc351c5
Fix MSVC 2008 warning about valid STL usage.

"warning C4996: 'std::copy': Function call with parameters that may be
unsafe - this call relies on the caller to check that the passed values
are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS.
See documentation on how to use Visual C++ 'Checked Iterators'".

Because the std::copy destination is a raw pointer.

Some solutions to get std::copy to work with pointers:
http://choorucode.com/2010/08/30/visual-c-c4996-warning-on-copy-with-array-parameters/

So yeah...Let's go with memcpy.

Change-Id: If0ff6277625cf1f63535bec72598587d4b934afa
Merge topic 'mingw-matrix4x4-warning' into master

61689b44 Fix MSVC 2008 warning about valid STL usage.
904e94df Fix mingw warnings on recent changes to Matrix4x4.