Remove .NET 4.5.1 and Portable 4.5 projects

.NET 3.5 and Portable 4.0 are the only targets needed, as we don't
use any .NET 4.5 features.
We still need .NET 3.5 target as it doesn't support portable libraries.

Author: angularsen

UnitsNet.sln

@@ -16,10 +16,6 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitsNet.Net35", "UnitsNet\
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitsNet.Tests", "UnitsNet.Tests\UnitsNet.Tests.csproj", "{6D74103A-9393-42E8-83A8-9E01F806E29D}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitsNet.Portable45", "UnitsNet\UnitsNet.Portable45.csproj", "{72BC5ED7-7496-4048-9233-7A4A843FE8A2}"
-EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitsNet.Net451", "UnitsNet\UnitsNet.Net451.csproj", "{8A855BF9-335F-4EC7-8473-D87883517910}"
-EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitsNet.Serialization.JsonNet.Net35", "UnitsNet.Serialization.JsonNet\UnitsNet.Serialization.JsonNet.Net35.csproj", "{2EF845D1-8177-4DF3-AEA9-5231E53CB30E}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UnitsNet.Serialization.JsonNet.Tests", "UnitsNet.Serialization.JsonNet.Tests\UnitsNet.Serialization.JsonNet.Tests.csproj", "{2A76FC53-E331-4CFA-83C0-93A212FD8F6E}"
@@ -72,26 +68,6 @@ Global
 		{6D74103A-9393-42E8-83A8-9E01F806E29D}.Release|ARM.ActiveCfg = Release|Any CPU
 		{6D74103A-9393-42E8-83A8-9E01F806E29D}.Release|x64.ActiveCfg = Release|Any CPU
 		{6D74103A-9393-42E8-83A8-9E01F806E29D}.Release|x86.ActiveCfg = Release|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Debug|ARM.ActiveCfg = Debug|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Release|Any CPU.Build.0 = Release|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Release|ARM.ActiveCfg = Release|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Release|x64.ActiveCfg = Release|Any CPU
-		{72BC5ED7-7496-4048-9233-7A4A843FE8A2}.Release|x86.ActiveCfg = Release|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Debug|ARM.ActiveCfg = Debug|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Release|Any CPU.Build.0 = Release|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Release|ARM.ActiveCfg = Release|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Release|x64.ActiveCfg = Release|Any CPU
-		{8A855BF9-335F-4EC7-8473-D87883517910}.Release|x86.ActiveCfg = Release|Any CPU
 		{2EF845D1-8177-4DF3-AEA9-5231E53CB30E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{2EF845D1-8177-4DF3-AEA9-5231E53CB30E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{2EF845D1-8177-4DF3-AEA9-5231E53CB30E}.Debug|ARM.ActiveCfg = Debug|Any CPU