FileCloseAction Update

Added stream insertion operator overload for FileCloseAction enum class
New File - CommonFunctions

Convenience functions that are commonly used by all of the classes. They
exist within a sub-namespace of the fileFunctions namespace.
Changes to FileWrapper and NumericFile

Basic Style Changes:
* used size() and lineSize() functions instead of getting them directly
from contents/fileContents
* used validateBounds() wherever bound validation was needed
* used auto less often to improve readability and to make the intent of
the code easier to understand
Added Functions:
* added sum functions
* added average functions
* added variance functions
* added standard deviation functions
* more convenience functions will be added in the future