Fix issue provided by [KorkhovPavel](https://github.com/KorkhovPavel)
ggsheet.py
- Improve the start_index and end_index finders in getCell(), getColumn(), and getRow().
- Fix the index range of the returned data from getCell(), getColumn(), and getRow().
- Sync the gen_scriptFile() to script.gs version 0.0.3.
script.gs
- Add "start" and "finish" to the getCell, getColumn, and getRow HTML headers.
- Fix the html title name from "Get Row Data" to "Get Column Data" in get column data mode.