docs(add-eslint-support.md): change .eslintrc with .eslintrc.json
docs(add-eslint-support.md): change .eslintrc with .eslintrc.json

flaiker/polymer-starter-kit,StartPolymer/polymer-starter-kit,gick/reveries-project,anthonybrown/polymer-starter-kit,StartPolymer/polymer-starter-kit,gick/mobile-polymer-starter-2,abdonrd/polymer-starter-kit,klarkc/polymer-loopback-starter-kit,gick/reveries-project,mtusk/polymer-starter-kit,stefanoantonel/brainpower,gick/mobile-polymer-starter-2,alexpaluzzi/polymer-starter-kit,semafloor/semafloor-test-alpha,anthonybrown/polymer-starter-kit,lordoftheflies/mlm-portal,markovuksanovic/polymer-starter-kit,gick/mobile-polymer-starter-2,Ex-ante-Labs/pivot-ahead,plusCubed/pluscubed-site,klarkc/polymer-loopback-starter-kit,Serious-Rage/poligomy,markovuksanovic/polymer-starter-kit,klarkc/polymer-loopback-starter-kit,abdonrd/polymer-starter-kit,alexpaluzzi/polymer-starter-kit,StartPolymer/polymer-starter-kit-plus,FaellCarvalho/Geo-Location,FaellCarvalho/Geo-Location,markovuksanovic/polymer-starter-kit,lordoftheflies/mlm-portal,stefanoantonel/brainpower,Serious-Rage/poligomy,semafloor/semafloor-test-alpha,flaiker/polymer-starter-kit,Ex-ante-Labs/shopper.ninja,gick/reveries-project,Ex-ante-Labs/shopper.ninja,Ex-ante-Labs/pivot-ahead,FaellCarvalho/Geo-Location,mtusk/polymer-starter-kit,lordoftheflies/mlm-portal,plusCubed/pluscubed-site,semafloor/semafloor-test-alpha,alexpaluzzi/polymer-starter-kit,Serious-Rage/poligomy,StartPolymer/polymer-starter-kit-plus