increase build version, better propagation in euf-egraph, handle assumptions in sat.smt

- increase build version to 4.12.1. This prepares updated release for MacOs-11 build on x86
- move literal propagation mode in euf-egraph to a callback and traversal of equivalence class. Track antecedent by newest equality instead of root. This makes equality propagation to literals have similar behavior as in legacy solver and appears to result in a speedup (10% fewer conflicts on QF_UF/QG-classification/qg5/iso_icl478.smt2 in preliminary testing)
- fix interaction of pre-processing and assumptions. Pre-processing has to freeze assumption literals so they don't get eliminated. This is similar to dependencies that are already frozen.

src/tactic/fpa/fpa2bv_tactic.h

@@ -5,15 +5,16 @@ Module Name:
 
     fpa2bv_tactic.h
 
-Abstract:
-
-    Tactic that converts floating points to bit-vectors
-
 Author:
 
     Christoph (cwinter) 2012-02-09
 
-Notes:
+Tactic Documentation:
+
+## Tactic fpa2bv
+
+### Short Description
+Converts floating points to bit-vector representation.
 
 --*/
 #pragma once

src/tactic/fpa/qffp_tactic.h

@@ -13,8 +13,17 @@ Author:
 
     Christoph (cwinter) 2012-01-16
 
-Notes:
+Tactic Documentation:
 
+## Tactic qffp
+
+### Short Description 
+Tactic for QF_FP formulas
+
+## Tactic qffpbv
+
+### Short Description 
+Tactic for QF_FPBV formulas
 
 --*/
 #pragma once

src/tactic/fpa/qffplra_tactic.h

@@ -14,7 +14,8 @@ Author:
 
     Christoph (cwinter) 2018-04-24
 
-Notes:
+
+## Tactic qffplra
 
 
 --*/