Further packaging of parser into api and extractor
Move removeFirstWord() from Extractor to Parser
Remove getTask() from Parser.
Create Extractor Interface and addExtractor to implement the interface
split extractor complete and test case added
exceptions added
question: should we remove first word, e.g "add"
add the implementation of splitted Extractor for Update, delete and view
in Parser.
Think it works.
deleted some commment
added exception in update so that 'update <ID>' must be followed by some
content.
Parser change tested
Merge branch 'SplitExtractor'