v0.4
Use native :numref: macro instead of numsec extension
Trivial: Add SPDX tags to source files
Add 'vibrator' to list of generic node names
cpus node: Make clock-frequency optional
Use valid MAC address example
State the 64-bit alignment requirement earlier
Add version to specification text
Add Devicetree logo to html and pdf output
Add an SVG logo
Update Arm copyright years thru 2021
