Speed up battery lowpass
Follow through with mission to loiter switch renaming
fix qmin/qmax types

qreal is a double on some platforms (x86) and a float on others (e.g. ARM), cast it to fix build errors like these:

src/ui/designer/QGCXYPlot.cc: In member function 'int
XYPlotCurve::appendData(const QPointF&)':
src/ui/designer/QGCXYPlot.cc:41:39: error: no matching function for call
to 'qMin(double&, qreal)'
             xmin = qMin(xmin, data.x());
                                       ^
src/ui/designer/QGCXYPlot.cc:41:39: note: candidate is:
In file included from
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtCore/qnamespace.h:45:0,
                 from
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtCore/qobjectdefs.h:45,
                 from
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtGui/qwindowdefs.h:45,
                 from
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtGui/qwidget.h:46,
                 from
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtGui/qdockwidget.h:45,
                 from
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtGui/QDockWidget:1,
                 from src/ui/designer/QGCXYPlot.cc:1:
/build/v2013.12/build/tmp-angstrom_v2013_12-eglibc/sysroots/sama5d3_xplained/usr/include/qt4/QtCore/qglobal.h:1213:34:
note: template<class T> const T& qMin(const T&, const T&)
 Q_DECL_CONSTEXPR inline const T &qMin(const T &a, const T &b) { return
(a < b) ? a : b; }
                                  ^

See http://www.qtcentre.org/archive/index.php/t-45475.html for some
background.

This fixes #625

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Merge pull request #626 from koenkooi/qminmax-fix

fix qmin/qmax types
fix value reading, only real32 was correct.
change to qt type
remove duplicate code
Merge pull request #629 from treymarc/mav_type

fix value reading, only real32 was correct.
add option "time serie" option to xyplot custom widget
Merge pull request #630 from treymarc/widget_xyplot_timeserie_patch

add option "time serie" option to the XYPlot widget
Merge branch 'master' of github.com:mavlink/qgroundcontrol into thread_test