makefile: add missing build type
runner: print executable commands
makefile: all modes capable of invariant check builds now
dbtest: emit warning message if built in debug mode
allocator: cache alignment
test: fix build error with factor-gc
tuple: make no overwrites mode actually work

assumption that new records are always larger than old records
no longer true with no-overwrites

also implement an optimization to avoid copying old values over if
the tuple writer does not require it