How about using a repository with branches or tags for releasing a new version? To me it seems to have the advantage that I'll be able to merge changes in the new version with my customizations of your code.
i think the stpes shall be:
1. merge com.radaee.pdf.Global class
2. replace other classes in com.radae.pdf
3. merge com.radaee.view classes.
4. replace assets and res subdr
5. merge other classes in com.radaee.util and com.radaee.reader
6. fix other compiler issues by manual, if any.