got 0.70

- avoid subtraction of values larger than int in qsort(3) comparison callbacks
- make 'got patch' handle git-style rename diffs
- store deltas in compressed form while packing, both in memory and cache file
- avoid O(N) loops over object ID lists while packing
- run the search for deltas to reuse in got-read-pack directly, for speed
- hook cmdline tests into 'make regress', this was overlooked earlier
- fix regression from 0.69 where packing tags fails if zero commits are packed
- map delta cache file into memory if possible while writing a pack file