Create Extract Reader class and Medication class

-Create Extract Reader to read database extract files. Assuming
pipe-delimited files as it is common for commas to appear in the
database extracted fields for medications, problems, allergies, etc.
-Create Medication class to represent a medication to be used in the
SubstanceAdministration section of the Medication module
-Add a testing folder and test file for medications. Future directory of
UnitTests.