Merge branch 'fixed-margins' of ssh://git.code.sf.net/p/apsampler/code into fixed-margins
some fixes
Harden null-stats permutation params and unify fixed-margins mode plumbing
todo 4i: the exit-0-on-error defect spans C and Perl
documentation: permutation modes, accumulator parameters, usage text
remove todo-notes.md, superseded by todo.md
working todo replacing the log-style notes
fixed non-ascii strande caracter