* Fix combo field appearances not being shown
* Fix V object type for choice and button fields
* Refactor form fill for combo and checkbox fields
* Add fill test case for text, combo and checkbox fields
* Prevent panic when flattening forms using a nil appearance generator
* Add configurable fallback font support for form fill/flatten
* Add appearance font to AcroForm DR
* Refactor DA process method
* Remove unnecessary font default size variable
* Minor refactor in the appearance generation functions
* Improve processDA appearance style method
* Use original font container if present in DR
* Maintain original appearance font autosizing behavior
* Parse form fields with embedded widget annotations
* Try matching fields both by partial and full names on form fill
* Use default font if widget font is not found when generating appearance
* Add JSON extract and fill test case
* Add packed predefined cmaps
* Add cmap cid range parsing
* Load base cmap for predefined cmaps
* Refactor pdfFont to Unicode methods
* Preserve CharcodeBytesToUnicode behavior
* Add support for CID-keyed Type 0 fonts
* Add method documentation for the cmap package
* Refactor and document charcode to Unicode conversion code
* Add more cmap parsing test cases
* Add more method documentation in the cmap package.
* Remove unused code from the bcmaps package
* Improve cmap test case
* Assume identity when encoder is missing on regenerating field appearance
* Add missing encoder log message
* Add inverse CMap mappings
* Add CMap encoder
* Address golint notices and small fix in the cmap package
* Keep smaller charcodes when generating cmap inverse mappings
* Update extractor test case
* Keep latest supplement charcodes/CIDs when computing inverse mappings
* Fix comment typo
