2020-03-14 v0.3

* Use the 'comment' attribute (as in comment() function) for spreadsheet
  imports in addition to 'comments' attribute (as before)
* Pass the ... arguments from read.opj to as.data.frame, making it
  possible to set stringsAsFactors and other parameters
* New 'tree' parameter to return the objects in a tree structure instead
  of a flat list

2019-03-14 v0.2-2

* Prevent truncation of long tables when importing large files
* Fix a memory leak possibly resulting from misuse of tree.hh library
* Decode strings using Riconv interface instead of Rcpp::Function
  call, making it much faster

2019-03-01 v0.2-1

* Added support for multi-spreadsheets, matrices and notes
* Correctly decode byte strings read from the file
* Fix undefined variable access found by UBSan

2019-02-06 v0.1-1

* Function read.opj imports individual spreadsheets as data.frames
