Adds microformats2 export format

[aaronpk]

Adds a microformats2 export format which exports each point as an h-geo entry.

Example output:

<p class="h-geo">
    <span class="p-name p-summary">Palio</span>
    <data class="p-latitude">45.5088</data>
    <data class="p-longitude">-122.64899</data>
</p>
<p class="h-geo">
    <span class="p-name p-summary">Cellar Door Coffee</span>
    <data class="p-latitude">45.50871</data>
    <data class="p-longitude">-122.65471</data>
</p>
<p class="h-geo">
    <span class="p-name p-summary">Ford Food &amp; Drink</span>
    <data class="p-latitude">45.50481</data>
    <data class="p-longitude">-122.65499</data>
</p>

[Zverik]

I've read about this microformat, but it seems not only it's still a draft, and having it in MapBBCode Share has no practical meaning for any users. Because those who know what the format is for, can easily process coordinate lists (e.g. CSV that the Share service can export) with perl or python scripts. That isn't a task that comes up often.

HTML and IFrame exporters (the only two that don't have importers and cannot be used in external systems) have obvious meaning and are important features of the service, while I don't see any reason in having MF2 h-geo exporter. This might open floodgates for other less-used geo formats (like gml — oh the horror), and I won't have a reason to not include those.

"Implementations" section for old geo microformat (there is no such section for h-geo) shows that authors don't usually type them by hand or include pieces of html markup in their pages, but use existing convenient tools or plugins that generate such markup, built into their services.