cgi: make it easier to extend meta tags
cgi: browserconfig.xml for MSIE

New browserconfig.xml files (two versions, one for the cgi-bin layout,
one for the /bbbike layout), and logo images for pinning, together
with a Makefile for creating the new files.
updated MANIFEST for html/msapp
removed the last reference to strpp
BrowserInfo: support for MSIE11 detection
cgi: geolocation and MSIE 10+11

Both MSIE 10 and 11 did not display the "locate me" link. Two things:
* the locate_me() javascript function was not called if $nice_abcmap
  etc. was not set
* document.implementation.hasFeature("CSS2", "2.0") does not work with
  MSIE 10 (but with MSIE 11)

Maybe other browsers (older MSIE?) may also profit from this change.
bbd2osm.t is known to fail with 5.18.x, make it a TODO test for now