Netlist compare: Ambiguity resolution through name matching now default (can be turned off) (#594)

* WIP: some refactoring

* WIP: some refactoring

* Netlist compare: introducing ambiguity resolution by net names

By default now net names are used for resolving ambiguities.
If net names match, they will be used to associate nets if the
choice is ambiguous. This is usually much faster and more reliable
than trying to resolve ambiguities through topology analysis.

This feature can be disabled using "consider_net_names(false)" in
the LVS script.

* Some refactoring, Jenkinsfile modified for better test coverage

testdata/lvs/double_height.lvsdb

@@ -295,8 +295,8 @@ Z(
   Z(
    N(2 3 1)
    N(3 5 1)
-   N(4 4 W)
-   N(5 6 W)
+   N(4 4 1)
+   N(5 6 1)
    N(1 1 1)
    N(6 2 1)
    P(1 2 1)

testdata/lvs/double_height2.lvs

@@ -131,5 +131,7 @@ connect_implicit("DOESNOTEXIST", "DOESNOTEXIST")
 netlist.simplify
 align
 
+consider_net_names(false)
+
 compare
 

testdata/lvs/double_height2_texts.lvs

@@ -131,5 +131,7 @@ connect_implicit("DOESNOTEXIST", "DOESNOTEXIST")
 netlist.simplify
 align
 
+consider_net_names(false)
+
 compare
 

testdata/lvs/floating.lvs

@@ -71,5 +71,7 @@ connect_global(ptie, "SUBSTRATE")
 netlist.simplify
 align
 
+consider_net_names(false)
+
 compare
 

testdata/lvs/invchain_cheat.lvs

@@ -126,5 +126,7 @@ connect_global(bulk, "SUBSTRATE")
 netlist.simplify
 align
 
+consider_net_names(false)
+
 compare
 

testdata/lvs/ringo_simple_blackboxing.lvs

@@ -83,5 +83,7 @@ netlist.purge
 netlist.combine_devices
 netlist.purge_nets
 
+consider_net_names(false)
+
 compare