read/write functionality done

with price, shipping, purchase date, seller, and additional notes
working for read and write. test included for exporting to/importing
from string form pushed to discogs, which is validated before changes
are made. worked on whole library.

.gitignore

@@ -1,3 +1,5 @@
 personal_access_token
 test.csv
+*.csv
+*.ods
 collection.gob