Allow advanced ranges
*Created originally on Bitbucket by [jarda-wien](https://bitbucket.org/%7Bed2d887f-0bc9-4940-9f54-35cbb995f15f%7D/)*
MS Excel can work with special range notations like 1:1 for the entire first row (column independent) or A:A for the first column (row independent).
The iter_rows() function throws an "Invalid cell coordinates exception" when trying this.
I propose to add code to support this kind of notation.
BR
Jaroslav
issue