Fix for image offset issue.
Extra tests for insert_image().
Added insert_image() to demo example.
Added TravisCI config file.
Fix for calcuation on load. Fixed #69
Prep for release 0.71.
Make generated filenames different from target filenames.
Fix filenames to allow paralled testing.
Fix to allow more generic JPEG handling.
Additional hyperlink test.
Fix for objects that cover formatted rows/columns.
Prep for release 0.72.
Reformatted dates as per CPAN::Changes::Spec
Merge pull request #70 from neilbowers/master

Reformatted Changes file as per CPAN::Changes::Spec
Test for comments overlying columns with non-default width.
Fix for tables added in non-sequential order.
Initial code for tick alignment.
Renamed position axis proprety.
Added chart legend font properties.
Added custom error bar option.