cropwatMUL 0.1.0

Initial CRAN release

• Added temperature-based FAO-56 Penman-Monteith reference evapotranspiration estimation.
• Added crop evapotranspiration and crop-water requirement calculations.
• Added multilocation simulation for one selected crop.
• Added USDA-SCS effective rainfall estimation.
• Added crop-coefficient and root-depth development functions.
• Added daily root-zone water balance and irrigation scheduling.
• Added daily, dekadal, monthly, and seasonal output tables.
• Added complete Excel and tab-delimited text-file exports.
• Added workbook input validation.
• Added a reproducible synthetic example dataset and workbook.
• Added automated tests and package documentation.