EPPlus

Merge branch 'develop' into feature/insert_rows_and_column_into_a_range

ExcelRangeBase.Insert - ConditionalFormatting, DataValidation and Drawing are now handled. Added more tests.

Issue #57 - Implemented Lcm function

Issue #57 Implemented Gcd function

WIP:More work on insert into range. Now Adjust tables, pivottables, merged cells and drawings. Issue #53