make node_t::branch() work with 1d and 2d
prepare node::getNeighbour() for use in 2d
make node::initialize work in 2d
make c_childs global: g_childs
add function node::getPoint() (untested)
for testing: simulate only one period in compaRunner
this plot from compaRunner doesn't make sense at all
Revert "this plot from compaRunner doesn't make sense at all"

This reverts commit 504d3eb3d009fe2dbf40dea89b987cd8789701ad.