SourceOperationFunction wordt nu goed getekend
Added the Integral

Signed-off-by: bvanr <henkibrij@hotmail.com>
MathOperationIntegral and MathSourceOperationIntegral now use the Dejavu Sans font
* Also slightly improved the drawing code of MathSourceOperationIntegral

Signed-off-by: Mark Kamsma <mark@markkamsma.nl>
Completed the helpers for MathOperationIntegral
+ MathOperationIntegral can now be saved/loaded to/from XML
+ MathOperationIntegral can now be evaluated
* Made the evaluation background white

Signed-off-by: Mark Kamsma <mark@markkamsma.nl>
Merge remote-tracking branch 'glenn/work' into pull
Strongly simplified the code for drawing MathSourceOperationFunction

Signed-off-by: Mark Kamsma <mark@markkamsma.nl>