Remove the use of DDG.strip_href

We no longer need to use DDG.strip_href for making HTML safe for DDG.strip_html. DDG.strip_html does everything for us and no longer executes scripts or loads images.
NJT: moved to consolidated Transit namespace
SEPTA: moved into consolidated Transit namespace
switched to text template
removed italics from content
Update Airlines source and icon to reflect current provider
don't really need the www for icon_url
Forecast: rework triggering.

Intended effect is to require temperature trigger to be preceded by
"current" or followed by "in/at/for".. or both.

In pursuit of this, also simplified the way forecast skip words
are maintained. At least I think it is simpler.

Also eliminated `meteo` trigger as it seems pretty esoteric and
unhelpful.

Intended to address #1170.
Forecast: readd meteo trigger word
Merge pull request #1173 from mwmiller/forecast_triggering

Forecast: rework triggering.
Merge pull request #1162 from duckduckgo/zaahir/airlines-attribution

Update Airlines source and icon to reflect current provider
Merge pull request #1159 from killerfish/expatsw

Expatistan: Switched to text template
Merge pull request #1157 from duckduckgo/mattr/transit-namespace

Consolidated Transit IAs into a namespace
Merge pull request #1146 from duckduckgo/jag/strip_href

Remove the use of DDG.strip_href