improvements to invisible text tests   - correctly track fgcolor   - only trigger if invisible text is actually printed (thinking ahead to     possible Bayes tweaks)   - don't retest tested color combinations   - weight R, G, B based on perceived luminosity (Rec. 709 values)   - scale both difference formulas to 0..765 for testing phase   - separate near-invisibility from total-invisibility (near invisibility     seems to have a better S/O since it is more likely to be intentional)
improvements to invisible text tests
  - correctly track fgcolor
  - only trigger if invisible text is actually printed (thinking ahead to
    possible Bayes tweaks)
  - don't retest tested color combinations
  - weight R, G, B based on perceived luminosity (Rec. 709 values)
  - scale both difference formulas to 0..765 for testing phase
  - separate near-invisibility from total-invisibility (near invisibility
    seems to have a better S/O since it is more likely to be intentional)


git-svn-id: d99324e817494df82bb0080d8e7ab74680731a10@4980 13f79535-47bb-0310-9956-ffa450edef68

apache/spamassassin,apache/spamassassin,apache/spamassassin,apache/spamassassin,apache/spamassassin