why:
Causes havoc in most bit fringe cases.
details:
When setting the head forward, the delta was wrongly registered from
the static "left" end (which limits the loop) rather than the moving
"right" end.
details:
For documentation, see comments in the file tx_pool.nim.
For prettified manual pages run 'make docs' in the nimbus directory and
point your web browser to the newly created 'docs' directory.