Added Preferences dialog
Simple mode
Add defaults into Tooltips from #885
Fix for Replicator 1 not finishing builds.

If the progress reaches 100% before last layer, the firmware erroneously stops reading the file.
regression test for combined infill #834

Guards against issue of slightly off-vertical walls triggering
extra infill on layers that should be empty when combining infill.
account for extrusion width when clearing layers for combined infill

Otherwise you get extraneous fill up against sloped walls in regions
of layers that should not have fill, like in #834.
avoid overlap of single layer and multilayer fill

A single-layer rectilinear or honeycomb fill under a low slope
wall/ceiling or extra perimeter will stick out from under the
overhang, because those fills get extended beyond their fill_surface
boundaries to purposely overlap perimeters. This causes interference
with multil-layer fills. This commit clips the single layer fill
boundaries a bit more where they interface with multi-layer fill
boundaries, to avoid overlap.
added file combineinfill.t
Disable extra perimeters if fill density is zero as they wouldn't be supported by anything and would just float inside the object. infill_only_where_needed should be the method of choice for hollow objects
Get rid of most calls to $Slic3r::flow
Remove $Slic3r::flow and $Slic3r::first_layer_flow
Don't validate the number of layers for infill combination, just limit it automatically. #993
Fix regression introduced in 91bcfc8a74425b1bfe3577460e5c3f48bcf17b9e
Bugfix: perimeter/infill overlap was calculated regardless of the infill extrusion width. #994
Bugfix: failure in launching on Windows with non-ASCII characters in username. #1011
Fixed regression in support material after recent flow refactoring. #1012
Bugfix: when using low layer heights and support material, the contact regions were generated with a negative height. #1013
Keep the full geometries in $layer->slices, including thin walls
Slight changes to the defaults
Use bridge math for the first solid infill layer above sparse infill. #240