[processing] changed dialog from critical to warning
[processing] simplified saga algorithms

Now it assumes matching grid extents and does not perform resampling
[processing] code cleaning. Removed debug sentences
[processing] remove unnecessary print sentences
[processing] fixed issue when opening loaded layers in batch interface (#10277)
[processing] removed debug line
[processing] minor change in ParameterFile to handle None values
[processing] major overhaul of lastools algorithms

Code contributed by Martin Isenburg
[processing] rewrote saga raster calculator as individual algorithm
[processing] added checkboxes to multiple input selector
[processing] removed interface module

now all access to the interface is done through qgis.utils.iface
[processing] fixed OutputFile constructor
[processing] fixed issue in modeler with hidden params
[processing] fixes in modeler to make multiple inputs work correctly