Fix for low byte chars in strings. Issue #86.
Fix for chart titles with eclamation mark.

Closes issue #83.
Remove duplicates and fix the order for set_column

Closes #82.
Minor doc changes.
Added support for non-contiguous chart ranges.

Issue #44.
Added date axis handling to charts.

Issue #73.
Moved the date handling routines into the utility module.
Added chart date axis example.
Prep for relase 0.5.2
Minor doc fixes.
Minor doc changes.
Added categories to setup.py.
Small fix in documentation for write_column
Merge pull request #90 from tax/master

Small fix in documentation for write_column
Merge pull request #1 from jmcnamara/master

Merge pull from jmcnamara/XlsxWriter