climatrends v1.0

Stable version with package's paper

climatrends v0.2

• Fix an issue in computing large areas with nasapower
• Add paper
• Add suggested CITATION
• Fix documentation typos
• Fix a bug in computing equation 'c' in GDD()
• Improve speed of functions GDD() and late_frost()
• package 'sf' is a suggestion not dependencies

climatrends v0.1.7

New implementations and modular expansion of data source