labeling.py refactoring, improved return values for QgsVectorFile editing

labeling.py MapCanvas context menu show shortcuts to label on selected QgsFeatures in linked QgsVectorLayer fields

added global accessors to labelshortcut layers

added LabelAttributeTableModel.shortcuts(QgsField)->list of auto-labels

added LabelAttributeType, LabelAttributeTableModel, LabelingDock

refactoring MapView dock

refactoring (import statements)

SpectralLibraryWidget (wip)

utils.py refactoring (loadUi -> loadUI, affects many widget classes)

added cursorlocationvalue.py + panel
added spectrallibraries.py + panel
added a couple of new icons
added trees.py (basic TreeModel system)

added # -*- coding: uft-8 -*-   and  # noinspection PyPep8Naming to each module
added GPL License statement to each module
added from __future__ import absolute_import to each module

moved loadUIFormClass(jp(DIR_UI, p)) to utils.py and (yessss!) removed an error occurred with newline character in *.ui inline HTML