v0.3.0

PanelDataTools v0.3.0

Diff since v0.2.0

Closed issues:

• Add ArgumentError or whatever is correct for when you use metadata version of functions without metadata (#19)
• Create lag/lead/tsfill etc with metadata for all functions (#20)

Merged pull requests:

• Leveraging metadata (#22) (@eirikbrandsaas)