expanded README.md and added example graphics.

Graphviz (the dot program) also does not accept dashes, the only accepted special character is underline

replaced by dashes. Optimized target search loop a bit

If the target option is used: check for link compatibility between targets and only consider files that are link compatible with first target

not start with a slash, add it

prevent them from being placed too close to each other

suppressed

'skipdirs'

that a symlink exists

the leading directory delimiter

program termination when an executable with an invalid ELF header is
analyzed