Ver 1.1

• Added exportSpreadsheets to export multiple data.frames in one go
• Made the api more consistent: always start with filePath if part of the arguments.
• renamed columnIndex() to as.columnIndex() and columnName() to as.columnName()
• renamed sheetName() to getSheetName()
• Added more tests.
• Fixed tests that left residuals outside of target dir
• Expanded docs