Provide version-based grouping functionality

[istanishev]

It would be nice if the tool supports grouping release information for multiple versions. A specific use case could be grouping release information for compatible releases and presenting only the latest one.

Example:

Instead of:
1.2.0.4 - ticket A
1.2.0.1 - ticket B
1.1.1.5 - ticket C
1.1.1.3 - ticket D
1.1.1.2 - ticket E

we could have:
1.2.0.4
ticket A
ticket B
1.1.1.5
ticket C
ticket D
ticket E