header (C) fixes
*.kmk: Removed all references to VBOX_SINGLE_MAKEFILE and all the associated ifndef sections.
Automated rebranding to Oracle copyright/license strings via filemuncher
Typo.
VBox-MakefileGuidelines: two more rules.
doc,Makefile.kmk: Draft for the makefile guidelines. (would've been of more use a year back, but better late than never?)