Defining stages as classes
Using the pipeline specification to construct the Python program
In this commit we have
1.Created a dictionary to translate stage names to class names.
2.Created a parser in Locate to handle /apple/
3.Defined class Stage as a superclass of the stage classes.
4.Stripped line ends in ReadFile and add them in WriteFile.
Further improvements to pipe3.py
added sqlite database
added developer's guide
Minor changes