Add a check around an optional function

My game crashes here if I update phaser.js to a new version. It happens
when my game switches to another State object.
Removed obsolete code in setTexture

This code has no side-effects besides assigning “textureChange”, which
is used nor reset anywhere else.
Merge pull request #1023 from lucbloom/sprite-textureChange-obsolete

Removed obsolete code in setTexture
added: .editorconfig file
Report key when failing

While loading sprite sheet.
Merge pull request #1026 from lucbloom/spritesheet-report-key

Report key when failing
Merge pull request #1024 from lucbloom/if-onShutDownCallback

Add a check around this optional function
Added: grunt-notify for jshint errors
Merge pull request #1027 from codevinsky/editor-config

added: .editorconfig file to help with jshint issues