startet implementatino of stackedbandinput dialog and required classes

fixed issue #64 "Plot Style Line Size (1pt already huge)". Solution wasQPen::setCosmetic(True) for using scale-independent line-width

(button to delete Qgsfields is enabled only in case none-standard fields exist)

speclib + temporal profile layers invisible to QGIS (for security reasons)

wip temporal profile saving

fixed Temporal profile expression evaluation

TemporalProfileCollection is now an in-memory TemporalProfileLayer(QgsVectorLayer)
added TemporalProfileTableModel, TemporalProfileTableFilterModel, TemporalProfileFeatureSelectionManager, TemporalProfileTableView

added @qgsfunctions plotStyleSymbolFillColor and plotStyleSymbol. this allows to synchronize th eplot visualization with the layer visualization of the Spectral Library

added default spectrum for spectral libraries

improved speclib CSV export