Fix buffer overflow if mir_cpuid_init() is invoked multiple times (#45)

According to the comment, it should be safe to call multiple times,
but e.g. the added unittest fails on my box (`_uCache_length` is
incremented and not reset).

At work, this occurs when mir-cpuid is linked statically into
multiple D binaries of some process - the CRT constructors share the
same global state on Linux (`_uCache_length` etc. - uniqued dynamic
symbols).

fixup

update deps

fixup

fixup caches

update dub sdl

fix index

fix index

new meson and ci configs (#43)

fix byte order for amd LeafExt1EInformation