rename column npa to amount_funded

want an column with a seperator
to catch bugs on MoneyDsl#money_attributes
the bug was fixed on pull-request 1
https://github.com/deepak/easy_rails_money/pull/1
two bugfixes

- https://github.com/deepak/easy_rails_money/pull/1
  when currency is set to nil, the money columns are set to nil as
  well (see changelog for 0.0.9.pre above)
  that code was buggy. so is a column was named "amount_funded"
  it would give the setter as "amountfunded=" rather than
  "amount_funded=".
  git sha1: c1d9f6a8160d5a075e78f625f177f6716715c637
- bugfix: validates_money was failing if allowed_currency was not passed
  the syntax is
  validates_money :principal, :repaid, :amount_funded, :allow_nil => false, :allowed_currency => %w[inr usd sgd]
  if we do not pass the last argument allowed_currency then it should
  validate that it is a legal Money::Currency
  that was not happenning because the Rails includes validations
  does not compare Symbols and strings