Add checksum and account ID support

[jbair06]

Checksums should appear wherever an account is loaded or entered.

For data entry, this requires that all text fields accept 0.0.1234, 0.0.1234-abcde, 1234, or 1234-abcde. In the latter two cases, the values should be converted to the proper form: 0.0.1234-abcde. If the checksum was manually entered, it should be validated allowing for incorrect checksums to be rejected and an error shown to the user.

For data selection, the accounts in a drop down list should show the checksum along side the account IDs.

For all other locations where an account is displayed, the checksum would appear along side the account ID.