Support for JSON1 extension

[heyzooi]

Support for JSON1 extension

https://www.sqlite.org/json1.html

[praeclarum]

Looks like the test didn't get updated

Build started 9/11/2018 4:38:26 PM.
Project "/Users/vagrant/git/tests/SQLite.Tests.csproj" on node 1 (default targets).
PrepareForBuild:
  Creating directory "bin/Debug/".
  Creating directory "obj/Debug/".
CoreCompile:
  /Library/Frameworks/Mono.framework/Versions/5.16.0/lib/mono/msbuild/15.0/bin/Roslyn/csc.exe /noconfig /nowarn:1701,1702 /nostdlib+ /errorreport:prompt /warn:4 /define:DEBUG /highentropyva+ /reference:/Library/Frameworks/Mono.framework/Versions/5.16.0/lib/mono/4.5-api/Microsoft.VisualBasic.dll /reference:/Library/Frameworks/Mono.framework/Versions/5.16.0/lib/mono/4.5-api/mscorlib.dll /reference:/Users/vagrant/git/packages/NUnit.2.6.4/lib/nunit.framework.dll /reference:/Library/Frameworks/Mono.framework/Versions/5.16.0/lib/mono/4.5-api/System.Core.dll /reference:/Library/Frameworks/Mono.framework/Versions/5.16.0/lib/mono/4.5-api/System.dll /debug+ /debug:portable /optimize- /out:obj/Debug/SQLite.Tests.dll /subsystemversion:6.00 /target:library /utf8output BooleanTest.cs ../src/SQLite.cs ByteArrayTest.cs ConcurrencyTest.cs EnumCacheTest.cs EnumNullableTest.cs EnumTest.cs ExceptionAssert.cs InsertTest.cs CreateTableTest.cs GuidTests.cs CreateTableImplicitTest.cs NotNullAttributeTest.cs SkipTest.cs CollateTest.cs ContainsTest.cs NullableTest.cs DropTableTest.cs LinqTest.cs TestDb.cs InheritanceTest.cs UnicodeTest.cs UniqueTest.cs StringQueryTest.cs AsyncTests.cs ../src/SQLiteAsync.cs MappingTest.cs DateTimeTest.cs TransactionTest.cs DeleteTest.cs ScalarTest.cs JoinTest.cs OpenTests.cs MigrationTest.cs EqualsTest.cs DateTimeOffsetTest.cs TableChangedTest.cs IgnoreTest.cs SQLCipherTest.cs "/var/folders/90/5stft2v13fb_m_gv3c8x9nwc0000gn/T/.NETFramework,Version=v4.5.AssemblyAttributes.cs"
/Users/vagrant/git/src/SQLite.cs(39,36): error CS0234: The type or namespace name 'Json' does not exist in the namespace 'System.Runtime.Serialization' (are you missing an assembly reference?) [/Users/vagrant/git/tests/SQLite.Tests.csproj]
Done Building Project "/Users/vagrant/git/tests/SQLite.Tests.csproj" (default targets) -- FAILED.
Build FAILED.
"/Users/vagrant/git/tests/SQLite.Tests.csproj" (default target) (1) ->
(CoreCompile target) -> 
  /Users/vagrant/git/src/SQLite.cs(39,36): error CS0234: The type or namespace name 'Json' does not exist in the namespace 'System.Runtime.Serialization' (are you missing an assembly reference?) [/Users/vagrant/git/tests/SQLite.Tests.csproj]
    0 Warning(s)
    1 Error(s)