condvar: added signal_all() and direct mutex variants.¹

1: The lock variants should be used in all normal cases. The mutex
variants make it easier to use when there are other constraints that
the lock is already obtained.
collections: replaced needless u32s with unsigned; tidy.

priority_queue: switched to bit shifting for sink() and swim().
log: added test variants.  premake: added --togo-test stub.¹

1: "test" mode will be used for extensive testing of modules and
as a way to keep extraneous debug logging around without comment
apocalypses, without incurring a cost unless needed.
priority_queue: added test mode and validation; removed grow().

premake: added TOGO_TEST_PRIORITY_QUEUE define to opt-togo-test.
log: moved format to macros; added traced variants; made error traced.
test: replaced cstdio with TOGO_LOG(); tidy.

test/general/headers: added includes for all headers (sorted).