Make compression more intelligent:
- we don't attempt to compress things under 44 bytes (empirical)
- we check whether larger objects actually compress
- we tag objects to indicate their compression
NUL means uncompressed and starts with NUL
x means gzipped and starts with x (handy)
u means uncompressed, drop the u
merge $1 $3 $2 || tkdiff -conflict $1 -o $1