Ability to pass an instance of SqlConnection to SqlServerStorage

Closes #253
Change the way how ExpirationManager obtains the connection
Return a message instead of throwing an error in HtmlHelper.DisplayJob

Fixes #254
Use OrdinalIgnoreCase comparer in SqlServerStorage.ToString

Fixes #230
Throwing `NotSupportedException` for methods returning `Task`

Closes #255.
Add release notes for 1.2.1
Bump version to 1.2.1
Remove Hangfire.Redis.nuspec
Pass SqlServerStorageOptions to queue provider

Fixes #256
Create default options in SqlServerStorage(SqlConnection) ctor
Change max Common.Logging dependency version to 2.2.0

Fixes #257
Add release notes for 1.2.2
Bump version to 1.2.2
Merge branch 'master' into Hangfire.Oracle

Conflicts:
	src/Hangfire.Sql/ExpirationManager.cs
	src/Hangfire.SqlServer/SqlServerConnection.cs
	src/Hangfire.SqlServer/SqlServerJobQueueProvider.cs
	src/Hangfire.SqlServer/SqlServerStorage.cs
	tests/Hangfire.SqlServer.Tests/ExpirationManagerFacts.cs
	tests/Hangfire.SqlServer.Tests/StorageFacts.cs