Entry logs adapter implementation

This pull request implements the skeleton and passes the tests put forth in pull request https://github.com/coldstar96/cse403/pull/62. It fulfills its role as being designed using test-driven-development.

For the UI, it adds a spinner to the EntryLogsActivity that lets you choose what sorting you want. Upon selecting it, the entries are sorted. Sorting is maintained after adding entries (the entry will appear in the correct position based on the sort selected).