Implementing dynamically typed command arguments to project
CodeSharper.Core/Common/Values/Argument:
  - Added a new Argument class for representing command arguments
CodeSharper.Core/Common/Values/ValueArgument and ErrorArgument:
  - Added value and error arguments of class hierarchy
CodeSharper.Core/Common/Values/Arguments:
  - Added a static class for handling arguments easily
CodeSharper.Tests.Core/Texts/ArgumentTestFixture:
  - Added a tests
CodeSharper.Core/Texts/TextSpan:
  - Fixing some bugs and code in TextSpan class and its helper class