Compatibility with versions <3.10 is going away.
As it happens, we're not using any CMake features that have changed
between 3.7 and 3.16, so bump the lowest version to 3.16.
Also remove the minimum version statement from the platform config
files --- they're all very simple files that are version independent;
and the version is checked elsewhere anyway.
Also, Fix style issue
A commit to fix style to make the PR go through.
Signed-off-by: Peter Chubb <Peter.Chubb@unsw.edu.au>
This commit also converts our own copyright headers to directly use
SPDX, but leaves all other copyright header intact, only adding the
SPDX ident. As far as possible this commit also merges multiple
Data61 copyright statements/headers into one for consistency.
