Merge pull request #10 from mprins/translation_update

NL translation update
Merge pull request #11 from nyantama/japanese-translation

Add Japanese translation.
bind captcha to current day
some cosmetic code cleanup
allow user to set the length of the CAPTCHA
obfuscate plain text

When the CAPTCHA code is in plain text in the HTML code (js, text,
math), random whitespace characters are introduced inbetween. This
should make it a little bit harder to parse the code from the HTML
source.
can translate the honeypot message
Merge pull request #12 from lainme/i18N

let the honeypot help message can be localized
Missing french translation
Merge pull request #13 from loranger/master

Simple contribution for missing french translation