Update README.md

Update Information about Tampermonkey auto update not working due to TM stable release which fixes that.
Merge pull request #349 from winkelement/patch-1

Update README.md
undo always using https for the portal image because some images are taken from panoramio which do not support https properly
Merge branch 'gh-pages' of github.com:breunigs/ingress-intel-total-conversion into gh-pages
allow quickly (de)selecting all layers by shift/ctrl/alt/meta clicking an entry in the layer chooser (fixes #232)
add note to user guide that this functionality is not yet available