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)

TimeSeriesViewer inherits QgisInterface
refactoring maptools
 - added mapcanvas.MapTools
 - TimeSeriesviewer.onShowProfile handles location based maptool requests (CursorLocation, Temproal/spectral prpofiles)

fixed bug in mapvisualization.py

MapCanvas: used MapCanvasLayerModel that support lazy loading of QgsMapLayer instances
MapViews can have individual vector layer sources for overlay

several updates to mapvisualization.py
cleanups + refactoring

fixed icon of mainwindow

mapvisualization: fixed several optical issues, connected buttons

changen MapViewUI layout form horizontal to vertical
added MapView specific crosshairs

first steps to change MapViewCollection UI

added __main__.py (in progress)
added option to load center pixel automatically

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

utils.py added loadIcon()
mapvisualization.py implemented MapCanvas loading activity bar

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

MapCanvas.setRenderer(renderer) handles QgsRasterRenderer and QgsFeaturerRendererV2

fixed labelSummary text update

changed DatumView.sizeHint()
SpatialTemporalVisualization uses RefreshTimer to handle very frequent refresh requests

MapCanvases get registered at responsible Controllers (STV, MV and DV)
utils.saveTransform(geom, crs1, crs2) takes care on invalid coordinate transformations

MapCanvas accesses STV directly
Setter functions take care on none-updates

less chained pyqtSignals -> MapCanvas accesses parent SpatialTemporalVisualization, MapView, etc. instances directly

temp. fix related to assert isinstance(tsv, TimeSeriesViewer) in SpatialTemporalVisualization() constructor

cleanup, refactoring,smaller fixes