Add top-ranges command

[fnash]

This PR suggests a new command top-ranges to follow the evolution of the volume of instances by the range as an indicator.

Given a directory of dump files, generated over process run time:

• dumpDir/001.json
• dumpDir/002.json
• dumpDir/003.json

bin/analyzer top-ranges dumpDir --show-zero

3 dump files found.
+--------+-------+
| Type   | Range |
+--------+-------+
| Foo    | 4     |
| string | 2     |
| Bar    | 0     |
+--------+-------+

It output the range (max instance count - min instance count) of the volume of objects of each type.