[gta02-core] fped: qualified measurement points

[Werner Almesberger]

An old limitation of fped is that measurements can't distinguish
different types of use of the same point. E.g., when using a frame
as a kind of "macro", it can sometimes be difficult to measure
things inside this frame.

With revision 5967, one can tell fped to only consider points that
have been reached via a certain set of frames. For example, in
http://svn.openmoko.org/trunk/gta02-core/modules/amp-10100492.fpd
the ground pads all come from frame "GND", which is in turn invoked
from the frames "G1", "G2", and so on.

In order to measure the size of each of the ground pads, the
measurements need to be qualified with the frame that defines the
parameters of that specific pad. This is done by adding the name(s)
of frames (*) to visit before the point, separated with slashes.
E.g.,

measx G1/GNDpad.ll -> G1/GNDpad.ur -1mm

(*) This list doesn't have to include all frames. If multiple frames
    are specified, they have to be in the order of invocation.

For now, qualified measurements can only be created by editing the
.fpd file, not through the GUI. They can be visualized, edited, and
saved, though.

AMP-10100492 is the footprint of the replacement SIM/SD card
holder. I've comitted a draft version in revision 5969. The design
takes some ideas from Dave's SMSN16, but much of the structure is
different, due to how AMP define the geometry.

Note that you need fped revision of 5967 or later to process this
file.

- Werner