Remove a bunch of unnecessary (and *theoretically* dangerous, in a very unlikely scenario involving custom cultures installed on a box) C# 7 string $"...{...}..." usages

Fixed some syntax errors in project.json files

Add InListStringSplitCount; when set, causes `in @foo` parameters to be implemented using string_split

Test for #524 (believed to be a failing test; cannot validate or fix until I get the latest tooling installed)

Note: build.sh needs love from OS X/*nix later to match

This fixes null refs with the DNX MSBuild targets when building from
Visual Studio.

Related issue: #520

RC2 Upgrade!

Tooling changes need to live in the repo now so the build doesn't FUBAR
every time we change the script.

Note: on a nuspec comparison, the following dependencies aren't there
anymore: Microsoft.CSharp, mscorlib, System, and System.Core aren't
explicitly specified in frameworkAssemblies anymore. The only one of
these I can imagine mattering is Microsoft.CSharp.

https://github.com/dotnet/corefx/issues/1612 is now closed, tests
working.

Nuget.org feed only, skip the 2 Sqlite tests until RC2+ packages with the fix are out of pre-release.

Add newer feed back **only for the tests projects**, Sqlite for example has bugs in rc1-final fixed in rc2-15948

.Net Core: remove floating versions (use stable ones on Nuget.org) and get this puppy back in action.

Also: it's 2016.

Note: no tests pass because there’s no integrated security option (or
widely available SQL server) on OS X at the moment. But the build and
test runners are up and going.