Fix getters for register with only wo fields
ioreg: No need to read from write-only registers
ioreg/parser: Nightly fallout
platformtree: Prefer indexing to _.get()
Allow registers to have non-'static lifetime
ioreg: Remove 'static from documentation example
Zinc now depends on shiny
ioreg: Add simple testcases
Merge pull request #145 from bgamari/ioreg-write-only

ioreg: write-only register fixes
Merge pull request #142 from bgamari/master

Nightly fallout
Merge pull request #128 from bgamari/ioreg-test

Add rudimentary tests for ioreg
ioreg::setter: Make documentation consistent with others
ioreg::parser: Rework doc comments

Add support for inner and trailing doc comments.
Merge pull request #135 from bgamari/ioreg-docs

ioreg: Extend doc comment syntax
k20::{sim, pin}: Port to ioregs!
k20::uart: Port to ioregs!