Adding more options for server selection.

Options are as follows:

- All servers via: servers=all
- Range of servers via: servers=5..10
- Selection of servers via: servers=1,3,7

When no servers are provided. Prompting user for y/n answer to run task on all servers.
Colorizing output.
Removing new line after prompt.
Adding install_all task.
Update Changelog.md
Update README.md