pxmake 0.8.0

Breaking changes

• Split sheet 'Table' into two sheets by language dependency. (#65)
• Split column 'position' in 'Variables' sheet into 'pivot' and 'order'. (#159)
• Check for illegal values in columns 'pivot' and 'type' in 'Variables sheet.
• Rename 'variable' and 'long_name' to 'variable-code' and 'variable-label'. (#144)
• Add check for language-dependent mandatory variables in Excel metadata.

New features

• Return rds object invisibly from pxmake and metamake. (#37)
• Support CONTVARIABLE. (#132)
• Preserve name of FIGURES variable through all data formats.

Bug fixes and minor improvements

• Rename all internal functions from 'source_data' to 'data'. (#151)
• Print error message without the name of the function that threw the error.
• Sort metadata before saving.