sanitize input
Fix numformat warnings
use is_numeric instead of is_string, to let "3" work
call graph: changed color of arrows/edges to grey for readability

call graph: changed color of arrows/edges to grey for better 
readability of the labels
Ignore build artifacts from Git
Missing config.m4 and tests from Git ignore
fixes PR #20 when using randomly generated run ids (better patch by @slava-vishnyakov)