Parse dates for transactions
Add test for parsing amounts

This will likely need to use BigDecimal eventually, but works for now.
Add a decimal amount to the fourth transaction
Modify transaction amount test to have cents
Add a memo to the first transaction
Parse transaction memos
Add some pending tests on where to go next
Add a slightly more helpful README
Added a note about example usage and pending tests
Filled out gemspec file
Removed a test that's covered by functional tests
Merge branch 'master' of https://github.com/McPolemic/YNAB4-Ruby into upstream

Conflicts:
	lib/ynab.rb
Domain change from BudgetParser to BudgetFolder

The BudgetParser class wasn't really parsing any budget data. It was,
instead just identifying the budget file by parsing several metadata
files in the YNAB budget directory. This change reflects the domain as
being the YNAB Budget Folder and provides methods for parsing the
metadata.

I'm still fairly unhappy with the Ynab::BudgetFolder#devices test, as it
feels very brittle and relies heavily upon the implementation of the
'#devices' method that it's testing. I'll look for ways to improve that.
Remove a reference spec file