Mary-Jo-Lisa; always the same... (Allow connection strings to be pulled by name from IConfiguration)

This change allows connection strings to be stored in any format supported by IConfiguration and then retrieved using just the name or the "name=" syntax in UseSqlServer and equivalent.

This change doesn't include anything to get IConfiguration registered and it doesn't include a way to get connection strings out of app.config/web.config, although that could potentially be done with an appropriate IConfiguration source.
Fixing build break caused my merge error.
Remove unused references from .csproj files
Target net451 in projects that depend on Microsoft.Data.Common

Resolves #177
Add csproj to sln and add skeleton code rowanmiller
Beginnings of a provider for Azure Table Storage.

Add null checks on public interfaces.
Batching is now configured per context.
Wrap Azure SDK in more testable interfaces and wrappers. Fix async issues on fetching
Update datastore to match new API.
Minor tweaks. Change batching setup to use configuration.
Whitespace fixes (R# code cleanup)
Implement HasTables. Add strings resource and check utilities. Wrap the CloudtTableClient in a testable interface
Add TODOs and more whitespace corrections
Culture invariant dates and other minor tweaks.
Add functional and unit testing to ATS requests. Enhance error handling.
Merge pull request #181 from natemcmaster/ats

Beginnings of a provider for Azure Table Storage.
Adds support for server-side filtering of data types supported by ATS.
Rebase on dev