Merge pull request #347 from JuliaRobotics/hotfix/1Q20/dfgnodeparamswhat

better inner constructor

Author: dehann

src/entities/AbstractDFG.jl

@@ -27,8 +27,8 @@ The common node parameters for variables and factors.
 mutable struct DFGNodeParams
     solvable::Int
     _internalId::Int64
+    DFGNodeParams(s1=0,s2=0) = new(s1,s2)
 end
-DFGNodeParams() = DFGNodeParams(0, 0)
 
 """
 $(TYPEDEF)

src/services/CommonAccessors.jl

@@ -106,7 +106,7 @@ getSolvable(var::Union{DFGVariable, DFGFactor})::Int = var._dfgNodeParams.solvab
 
 Get 'solvable' parameter for either a variable or factor.
 """
-function getSolvable(dfg::AbstractDFG, sym::Symbol)
+function getSolvable(dfg::AbstractDFG, sym::Symbol)::Int
   if isVariable(dfg, sym)
     return getVariable(dfg, sym)._dfgNodeParams.solvable
   elseif isFactor(dfg, sym)