Add a UI to the Windows installer

We'll be able to control whether the app starts up or not after
installation.
Switch license file to rtf and to the right license
Merge tag '4.1.0' into windows-installer-ui

4.1.0
Update license reference
Win Dogstreams| Remove unreachable part of the code
Win Dogstreams| Allow to load modules from windows
Win Dogstreams| Remove default argument that could never be used
Win Dogstreams| Split the value from the configuration file correctly
Win Dogstreams| Reorganize imports
Win Dogstreams | Extract colon split code

Also use correct examples for windows conf
Win Dogstream| Fix failing module load test
Win dogstreams| in win split test, leave Platform in a correct state
Update CHANGELOG.md
Update CHANGELOG.md
Merge pull request #1056 from DataDog/rudy/win-dogstream

Rudy/win dogstream
Update Changelog
Update CHANGELOG.md
Win SNMP| Bundle pysnmp with the windows agent
Win SNMP| Correct mib inclusion
Win SNMP| Pysnmp imports are reaaally fun