Maps back and forward history to back and forward buttons on a 5 button mouse.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57285 954f8c5b-7b00-dc11-b283-0030488c597c
Code cleanup:
Comment no longer relevant as UI button exists to create a new directory.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57286 954f8c5b-7b00-dc11-b283-0030488c597c
code cleanup: warn undefined compiler defines.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57287 954f8c5b-7b00-dc11-b283-0030488c597c