This patch adds the `USING_AK_GLOBALLY` macro which is enabled by
default, but can be overridden by build flags.
This is a step towards integrating Jakt and AK types.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
Also add IndexSequence and associated helpers. The TypeList class can be
queried for what type is at a certain index, and there are two helper
functions: for_each_type, and for_each_type_zipped.
for_each_type will invoke a lambda with a TypeWrapper object for
each type in the type list. The original type can be obtained by
extracting the ::Type from the type of your generic lambda's one
argument.
for_each_type_zipped will walk two TypeLists in lockstep and pass a
TypeWrapper object for the current index in each list to a generic
lambda. The original type from the TypeList can again be extracted via
the ::Type of the generic lambda's two parameters.
