Started generating chart SVG
Sanitized AgWindow - Removed timestamp member

It can be retrieved from the Window's chart, and is rarely used
Finished base XML generation code
Fixed example chart data

Longitude and latitude were exchanged
Added CSS and XSL file for later use
Created pure-path version for sign Virgo
Added exslt as a build dependency
Now initializing eXSLT together with libXML
Finished SVG generating code
Added WebKitGtk 3.0 as a build dependency
Created web view for the SVG chart
Now installing XSL and CSS files
Fixed up XSL file, so it displays aspects instead of antiscia
Added libxslt initialization to main()

It worked without this. Just to be on the safe side...
Temporarily changing locale to C while generating the SVG image

With locales that have a character other than dot as a decimal separator,
the generated SVG is messed up (due to a libxml2 bug)
Now setting the CSS file path as a parameter

This will allow us to use separate CSS and XSLT files (e.g. themes) later
Added base_url to webkit load function

Without that, using external CSS files is impossible
Added some cleanup functions
Resizing webkit view when the chart tab is activated

This is temporary, it really should resize automatically
Merge branch 'chart'