assets: update flot to 0.8.3
static/js/flight.js: explicitly add phases layer
static/js/flight.js: store phase table inside placeholder
flight.js: initialize phases table only once per element
flight.js: unselect all other phase table selections

Prepare to have multiple phase/leg tables
templates/flighs/view.jinja: make leg tables clickable
flight.js: make gjslinter happy
Merge PR #362: Select and highlight legs in legs statistics