- changed variable name from "rep" to "issue" in GetAuthorsDict method
- changed class name from TimeSheet to Timesheet
- changed method name from SetAuthorTime to SetAuthorTimeSpent
- added SetAuthorTimeFormat method and used it in SetAuthorsTimeFormat
- changed methods from public static to private static: GetAuthorsDict, Add, SetAuthorTimeSpent
- changed SetTotalTime method from public static to private