Change lib directory name in Guardfile(Did not change gem name)
Add number-rows-repeated sheet in general_datas.ods
Add created_from_excel2010.ods
Add test for sheet included number-rows-repeated
Add test for reading created from excel
Add test to call Sheet#each_row two times

Sheet#each_row to use the table-rows-repeated If you call
the Sheet#each_row first.
On the other hand Sheet#each_row to use the @cell If you
call the Sheet#each_row after the first time.
Confirm iterator times

If the number of iterations are 0, should statement is not executed.
Use table:number-rows-repeated attribute
Add force option argument in Sheet#each_row

File converted from excel has full size row.
These cells almost have not data, and to read all rows spend many time.
For this reason, Sheet#each_row(and each, each_column) not want to read these rows.
But Sheet#[] have to read cells that are specified by row, column.
Then Sheet#[] specify force option, but another methods don't specify force option.
Break if row_index are more than rows-repeated
Use Sheet#each_row in Sheet#each
Use each_row in Sheet#[]
Use each_row in Sheet#each_column
Add break condition in Sheet#row_cells
Return Emumerator unless block Sheet#each, Sheet#each_row, Sheet#each_column
Fix README.md
Update version