Fix mean value calculation for Uniform distribution (#43)

Author: sean-reed

src/SimSharp/Random/Distributions.cs

@@ -366,7 +366,7 @@ public class Uniform : Distribution<double> {
     public double Lower => _lower;
     public double Upper => _upper;
 
-    public double Mean => 0.5 * (_upper - _lower);
+    public double Mean =>  0.5 * (_lower + _upper);
     public double StdDev => Math.Sqrt((_upper - _lower) * (_upper - _lower) / 12.0);
 
     public Uniform(double lower, double upperExclusive) {
@@ -390,7 +390,7 @@ public class UniformTime : Distribution<TimeSpan> {
 
     public TimeSpan Lower => _lower;
     public TimeSpan Upper => _upper;
-    public TimeSpan MeanTime => TimeSpan.FromSeconds(0.5 * (_upper - _lower).TotalSeconds);
+    public TimeSpan MeanTime => TimeSpan.FromSeconds(0.5 * (_lower + _upper).TotalSeconds);
     public TimeSpan StdDevTime => TimeSpan.FromSeconds(Math.Sqrt((_upper - _lower).TotalSeconds * (_upper - _lower).TotalSeconds / 12.0));
 
     public UniformTime(TimeSpan lower, TimeSpan upperExclusive) {

src/SimSharp/SimSharp.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;net45</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;net462</TargetFrameworks>
     <SignAssembly>True</SignAssembly>
     <AssemblyOriginatorKeyFile>SimSharp.snk</AssemblyOriginatorKeyFile>
     <DelaySign>False</DelaySign>
@@ -33,7 +33,7 @@ Sim# allows modeling processes easily and with little boiler plate code. A proce
     1) All of the RandXXX methods in class Simulation have been marked as obsolete.
     2) All of the random TimeoutXXX methods in class Simulation have been marked as obsolete.
 
-    To port code, it is advised to add &quot;using static SimSharp.Distributions&quot; to the using section and change e.g.
+    To port code, it is advised to add "using static SimSharp.Distributions" to the using section and change e.g.
     env.RandUniform(1, 2) to env.Rand(UNIF(1, 2))
     env.RandNormalPositive(3, 0.5) to env.Rand(POS(N(3, 0.5)))
     env.RandLogNormal(1, 2) to env.Rand(LNORM(1, 2))