Recommendation is to avoid using the year nomenclature as this
information is already encoded in the git repo. Avoids needing to
repeatly update.
Also updates AUTHORS.txt from current repo with contributor names
F_Cu = 0
B_Cu = 2
Remaining internal copper layers are even and incrementing
Non-copper layers are odd and incrementing.
This means that we can no longer do things like:
for( PCB_LAYER_ID layer = F_Cu; layer <= B_Cu; ++layer)
Instead, we have the class LAYER_RANGE:
for( PCB_LAYER_ID layer : LAYER_RANGE( F_Cu, B_Cu) )
Similarly, gt/lt tests should not refer to the integer value of the
layer. We have functions such as IsCopperLayer to test whether a layer
is copper or not.
When using the connectivity RTree, the third dimension is layer, so we
provide B_Cu with the special INT_MAX value, ensuring that elements
between F_Cu and B_Cu will be identified. There is a new, special
function GetBoardLayer() for interfacing with CN_ITEMS
Similarly, PNS layers remain unchanged and sequential. A set of
interface functions is provided to map PNS layers to Board layers and
back. This allows the PNS_LAYER_RANGE to function as expected
