Bounding box calculation optimalization

Signed-off-by: bvanr <henkibrij@hotmail.com>
fixed integral in integral

Signed-off-by: bvanr <henkibrij@hotmail.com>
fixed integral in integral

Signed-off-by: bvanr <henkibrij@hotmail.com>
Merge branch 'basbranch4' into basbranch2

Conflicts:
	src/org/teaminfty/math_dragon/view/math/operation/Integral.java
Merge remote-tracking branch 'bas/basbranch2' into work
A warning is now shown when variables have been substituted (fixes #149)

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