Batch metrics by timestamp/measurement/type into a single line

[hawson]

These lines:

• cpu,hostname=stardust cpu_user=1.3 1460916757505296000
• cpu,hostname=stardust cpu_system=0.5 1460916757505296000
• cpu,hostname=stardust cpu_temp=84i 1460916757505296000
• cpu,hostname=stardust cpu_speed=1700i 1460916757505458000
• cpu,hostname=blackhole cpu_speed=1700i 1460916757505296000
• cpu,hostname=blackhole cpu_temp=85i 1460916757505296000

Could be merged:

• cpu,hostname=stardust cpu_user=1.3,cpu_system=0.5 1460916757505296000
• cpu,hostname=stardust cpu_temp=84i 1460916757505296000
• cpu,hostname=stardust cpu_speed=1700i 1460916757505458000
• cpu,hostname=blackhole cpu_speed=1700i,cpu_temp=84 1460916757505296000

[hawson]

It appears that having the same type is no longer (if ever?) a requirement. So the original six lines could be compacted a bit more:

• cpu,hostname=stardust cpu_user=1.3,cpu_system=0.5,cpu_temp=84i 1460916757505296000
• cpu,hostname=stardust cpu_speed=1700i 1460916757505458000
• cpu,hostname=blackhole cpu_speed=1700i,cpu_temp=85i 1460916757505296000