According to this page on the Lightning Design System, the unmanaged package has been deprecated due to SLDS being available in Salesforce without need for a static resource. However, I'm having trouble grabbing SLDS icons for use in lightning components still.
Are the SLDS icons available without the need for a static resource? If so, what's the path I should use for the SVG?
Best Answer
They are not natively available in lightning. You will need to get a static resource. There is a great explanation on why and the component workaround that you can use until it is supported.
Lightning SVG Component Helper
Since posting, lightning components can now extend SLDS by using the force:slds markup.
force:slds tag release notes
Lightning Icons can then be used by using the lightning:icon markup:
lightning:icon