net6.0

net5.0 travis-ci config update

CHANGELOG.md updated

Refactoring

Version 1.7.1

 - Nflags class obsoleted in favorite of Cli class. (#20)

v.1.7.0

Fixed Kestrel Example aspnetcore version

Introduced support for environment variables and more (#4)

# 1.5.0
 * Introduced Flag/Option/Paraemter/ParameterSeries builders
 * Flag/Option/Paraemter/ParameterSeries Attributes changed to support named arguments
 * Introduced support for binding Environment Variables

Generics, PrintHelpOnExecute, DefaultCommands

 * Generic custom args command registration
 * Method RegisterSubcommand marked as obsolete and RegisterCommand method introduced
 * Introduced PrintHelpOnExecute
 * Introduced default commands

v. 1.3.1 - readme fixed