[BUG] Droppable value displayed as a decimal but should be whole number

[bschoening]

The column 'droppable' is reported with a decimal place in ic-sstable-tools sstables, but the value appears that it should be an integer. The decimal place is confusing as it suggest the number maybe is in KB or something similar.

Also, it might be helpful to add 'TS' as 'droppableTS:'

i.e.,
"avgPartitionSize": "23.3 kB",
"maxPartitionSize": "454.8 kB",
"avgColumnCount": 1642,
"maxColumnCount": 29521,
"droppable": "0.0"

To Reproduce
Steps to reproduce the behavior:

Expected behavior
A clear and concise description of what you expected to happen.

System and versions (please complete the following information):

• OS, Cassandra version, Java version, SSTable tools version

Additional context
Add any other context about the problem here.