added more information in the varaible "flag"; flags can now be a integer from 0-3; information is according to help-files and vignette
code changes that appear only in the changelist but are not systemic otherwise are now considered as well
harmonize_cn8() and harmonize_pc8() now show expected calculation time
harmonize_cn8() and harmonize_pc8() have a new argument "harmonize.to", which allows the user to define if harmonization is done towards the first or last year of the period of interest.
utilize_cn8() and utilize_pc8() have a new argument "base", which allows the user to define which plus-codes (CN8plus or HS6plus) are used as a base for calculating added/dropped/same products and their corresponding values.
Huge data update: PC8 data is now available from 2001 to 2021; CN8 data is now available from 1995 to 2022; BEC Rev. 5 is now available
more background information about idea of the harmonization was added to the vignette
renamed all functions; "." replaced by "_"
minor bug fixes in harmonize_pc8(), affecting HS6plus codes
default value of utilize_cn8() and utilize_pc8() changed
new argument "value" of utilize_cn8() and utilize_pc8() for including various quantities, user can obtain values of same/added/dropped products