checksums

checksums is used at run time in 4 crates.

Number of dependers	checksums version	Downloads/month
2	0.9.1	150
1	0.7.1	160
1	0.5.5	11

Depender			checksums version
		csum		=0.9.1
		tarsum		^0.7.0
		tmpshare		^0.5.5
		cramino		^0.9.1