1.4.5 features (#319)

* Changes:
Improve precise wall
Port PS2.6 overhang slowdown feature
Implement overhang fan for new overhang slowdown algo
Add option to switch between classic/new overhang slowdown implementation
Set Arachne as default engine
Small adjustment of temp calibration range
turn off small perimeter by default
Small UI tweaks
Change default top_surface_pattern to monotonic
Fine tune jerk

Signed-off-by: SoftFever <softfeverever@gmail.com>

* Disable optimizations for RelWithDebInfo

Signed-off-by: SoftFever <softfeverever@gmail.com>

* fix an issue that max volumetirc/vfa calibration can't send to print

Signed-off-by: SoftFever <softfeverever@gmail.com>
#322

* fix build errors

Signed-off-by: SoftFever <softfeverever@gmail.com>

---------

Signed-off-by: SoftFever <softfeverever@gmail.com>

src/libslic3r/PrintObject.cpp

@@ -826,7 +826,8 @@ bool PrintObject::invalidate_state_by_config_options(
             //BBS
             || opt_key == "enable_overhang_speed"
             || opt_key == "detect_thin_wall"
-            || opt_key == "precise_outer_wall") {
+            || opt_key == "precise_outer_wall"
+            || opt_key == "overhang_speed_classic") {
             steps.emplace_back(posPerimeters);
             steps.emplace_back(posSupportMaterial);
         } else if (opt_key == "bridge_flow" || opt_key == "bridge_density") {