Support also "/" for Parameters
-Adding AddEnumValuesToHelpText option to HelpText.cs to list enum values when generating help.
-Refactoring to simplify code.
Fixed case where there are duplicate value arguments
Added unit test to demonstrate duplicate tokens
Update Readme.txt - "New Code:" description

Simple string -> char correction
One option with Required doesn't need to be filled if another item of its MutualSet is provided. In another words: only one item of a MutualSet with all items Required need to be provided.
Added support for defining options in interfaces
Merge branch 'pr/119'
Merge branch 'pr/118'
Merge branch 'pr/111'
Merge branch 'pr/103'

Conflicts:
	src/CommandLine/Core/Tokenizer.cs
Merge branch 'pr/97'

Conflicts:
	src/CommandLine.Tests/CommandLine.Tests.csproj