Captcha and design works.

Added captcha generation. As we're working without JS - there is no
possibility to reload image, only if user will reload whole web page.

Some design works - set monospace font for paste textarea (will
use system-defined default monospace font) and lowered font size
in paste views.

vendor/github.com/dchest/captcha/.gitignore

@@ -0,0 +1,8 @@
+# Generated test captchas
+capgen/*.png
+capgen/*.wav
+
+# Programs
+capgen/capgen
+cangensounds/cangensounds
+capexample/capexample