Use keydown for key press detection in chat.

Fixes tab completion in Chrome. Closes #45.
add ability to filter by portal level. You can access the feature from the layer selector just as before. Fixes #8 and some of #12
Merge pull request #50 from firetech/fixes

Use keydown for key press detection in chat.
add fallback for Opera because it doesn’t support calc. See #49
Merge branch 'gh-pages' of github.com:breunigs/ingress-intel-total-conversion into gh-pages
Merge remote-tracking branch 'upstream/gh-pages' into gh-pages