Docs for 4.8.1

[Jack]

I finally sat down and worked on updating the manual for 4.8.1.

I updated the version and copyright dates,  changing the copyright (for  
both the program and the documentation) to 2000-2017 instead of listing  
all the years individually.  I updated the date and version only in  
those specific docbook files I updated.  I'm pretty sure the doc team  
does not think the date and version should be changed in a docbook file  
unless that file has actually been updated for the new version, or at  
least fully confirmed to be still accurate, so I think it's ok to leave  
them alone.

I updated the "what's new" by going through the list of bugs using the  
filter that Ralf created and posted a while back.

I added a minor note to the import/export page about using the QIF  
profile to change character set.

If there are any other specific changes to the program that really  
should be included in the manual, let me know, and I'll add them.

I have not yet pushed my changes up to git.  I can do that, or else  
post the diff here or to a reviewboard entry, in case anyone wishes to  
review them.

Jack