Basic XML reading functionality

Code now has examples of ways of reading data.
Added data.xml

file has example data in it
Updates for part 3

data.xml updated to provide the relevant data for part 3. Code
previously in constructor is now in processXML function so that it is
executed only after the file has loaded.
Part 3 completed

Code consolidated. Meets all criteria for part 3.
Updates
Updated readme
Merge branch 'master' of https://github.com/jamesmangos/flash-challenge-3