Changed Pagie-Hogeweg problem to use absolute error instead of square error.
Also, made runs stop with success if hits == 0.
Moved problem-specific report to start of report.
Moved check for success into report function, which is now called
report-and-check-for-success. Also, made it so if an individual has
:success true, then report will treat it as a success even if it doesn't
have total-error < error-threshold.
Added lexicase report that prints lexicase info whenever lexicase selection
is used.
Changed printing of programs to call pr-str on them first, to make sure their
strings are printed in computer-readable format.
Added printing of percent parens for best program and average for population.
thelmuth/fix-pagie