fixed a bug + removed unused function

+ fixed Bug: in rare cases the new node formed after a coalescence was not local even
when it should have been
+ the updateBranchBelowEvent thing never occurs, because two notes can only be
active above the local tree, i.e. they cannot coalescence into local nodes. The
only way to stop if two nodes are active is that these nodes come together,
which makes updating of branches easy.