Bug Fixes: bigint, datetime2, big-endian, unit-tests

• Use int instead of bigint when possible (based on size of data) to work with drivers that don't support bigint at all. Thanks @gordthompson and @v-makouz
• Support SQL Server datetime2 precision. Previously more data was passed than the column precision causing an error. Thanks @PrinsEdje80, @v-makouz, and @v-chojas
• Make Informix unit tests work again. Thanks @richard-reece
• Correct encoding error on big-endian machines for connection errors. Default to native UTF16 instead of UTF16-LE. Thanks @kadler
• Fix MySQL unit tests. Thanks @gordthompson