ZA: speed up person detail page load times
ZA: speed up person detail page load times

Finding recent speeches in each section is much faster if you use the
tags associated with the speeches rather than do a recursive search from
the top level section.

Fixes #1500

patricmutwiri/pombola,geoffkilpin/pombola,mysociety/pombola,patricmutwiri/pombola,patricmutwiri/pombola,mysociety/pombola,mysociety/pombola,geoffkilpin/pombola,ken-muturi/pombola,patricmutwiri/pombola,geoffkilpin/pombola,geoffkilpin/pombola,geoffkilpin/pombola,ken-muturi/pombola,mysociety/pombola,ken-muturi/pombola,patricmutwiri/pombola,ken-muturi/pombola,ken-muturi/pombola,mysociety/pombola,patricmutwiri/pombola,geoffkilpin/pombola,mysociety/pombola,ken-muturi/pombola