Refactor the N900 light sensor.
Refactor the N900 light sensor.

There's now more-easily-tunable numbers and histeresis.
The values used are still just guessed though.

qtproject/qt-mobility,tmcguire/qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,enthought/qt-mobility,tmcguire/qt-mobility,KDE/android-qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility