[oe] DOCUMENTATION of R* variables like RDEPENDS

[matti kaasinen]

Hi developers!

I was faced with problems when using RDEPENDS dependencies without
_${PN} extensions. Actually both conventions were mixed with my
OE-classic design. I was guided to correct direction by Angstrom
community's kind guidance. However, I feel OE official User Manual
has documentation problem regarding these R* variables that
link below describes in more details:

http://lists.linuxtogo.org/pipermail/angstrom-distro-devel/2012-April/005944.html

take care,
Matti