The proptools functions took an inconsistent variety of
struct and *struct types. Some methods even took a struct
but returned a *struct. Make all the exported methods
take a *struct, with internal helpers for the ones that need
to take a struct.
Test: proptools tests
Change-Id: I60ce212606e96adcef66c531d57f69c39e1a1638
Blueprint is a meta-build system that reads in Blueprints files that describe
modules that need to be built, and produces a
Ninja manifest describing the commands that
need to be run and their dependencies. Where most build systems use built-in
rules or a domain-specific language to describe the logic for converting module
descriptions to build rules, Blueprint delegates this to per-project build
logic written in Go. For large, heterogenous projects this allows the inherent
complexity of the build logic to be maintained in a high-level language, while
still allowing simple changes to individual modules by modifying easy to
understand Blueprints files.