[refactoring] Started to refactor the Command model in CodeSharper. Added a new ArgumentWrapper class which is responsible for argument-checking. Added a new Runnable class which is a lightweight solution for creating argument independent commands for text manipulating.

CodeSharper.Core/Common/Runnables/ArgumentWrapper:
  - Added a new class
  - Responsible for argument-checking
CodeSharper.Core/Common/Runnables/IArgumentWrapper:
  - Added an interface for ArgumentWrapper
CodeSharper.Core/Common/Runnables/ValueArgumentWrapper:
  - Represents an argument wrapper for creating values (ValueArguments)
CodeSharper.Core/Common/Runnables/ReplaceTextRunnable:
  - Represent a light-weight solution instead of ReplaceTextCommand
CodeSharper.Core/Common/Runnables/ToUpperCaseRunnable and ToLowerCaseRunnable:
  - Represent light-weight solutions instead of ToUpperCaseCommand and ToLowerCaseCommand
CodeSharper.Core/Common/Runnables/IRunnable:
  - Added a new class
  - Represents a light-weight transformation command.