Chart options

Release adds a number of options for charts and fixes scattered warnings and code issues

Worksheets

• Preserve headerFooter elements

Charts

• Added axis names
• Added axis tick labels position

Fixes

• [XLSX-1] mistyped Chart::setChartTytle renamed to setChatTitle
• Fix boolean values parsing

Merge with Alexander-r/master

This release is result of merging with Alexander-r/master branch and adds following features:

Charts

• Added ChartLine class to handle chart line's properties: a name (for legend), a wideness, a colour, a marker
• Added Marker class to handle chart marker's properties: a symbol (like star, cross, circle etc..) and size
• Add Chart::setChartTitle() method to set chart's title
• Add number of Chart class methods to control chart's axis and grid lines (setAxisMaxScope, setAxisMinScope, setAxisMaxAuto, setAxisMinAuto, enableAxisMajorGridLines, enableAxisMinorGridLines)
• Add Chart::setShowLegend() method to define chart's legend position

Cell formats

• Add a number of Format::custom helpers to produce useful formats.

Formulas

• Add Formula class to create and control cell formulas

Printing support

• Add printOptions, pageSetup, pageMargins

Other

• Defined names
• Panes splitting
• Fix bugs, etc...

Actually there is a lot of weakly described code and is a lack of test cases too. So all this on your own risk...

Initial release

Release was tagged with next minor version after previous known from branch VSRonin/QtXlsxWriter