Adding decoding of multipart identifiers, default schema workaround (#295)

This change adds a couple things

_Multipart Identifier Decoding_
The ability to decode a multipart identifier (with or without escaping) has been added to the SqlScriptFormatter utility class. This code is utilized to split a table name provided to the edit/initialize request into schema and table name.

_Default Schema Workaround_
The code that retrieves the SMO metadata objects originally used the `[]` operator to access the objects. Due to a bug(?) in SMO, this results in problems when loading tables without a default schema (in our case if you're logged in as SA). Using the metadata object constructors gets around this issue, we are explicitly using them.

* Adding decoding of multipart identifiers
Adding code fix for default schema issue

* Adding some more localizable strings for errors when loading metadata

* Adding localization files... again?

* Changes as per pull request comments

src/Microsoft.SqlTools.ServiceLayer/Localization/sr.strings

@@ -180,6 +180,10 @@ EditDataSessionAlreadyInitializing = Edit session has already been initialized o
 
 EditDataMetadataNotExtended = Table metadata does not have extended properties
 
+EditDataMetadataObjectNameRequired = A object name must be provided
+
+EditDataMetadataTooManyIdentifiers = Explicitly specifying server or database is not supported
+
 EditDataFilteringNegativeLimit = Result limit cannot be negative
 
 EditDataUnsupportedObjectType(string typeName) = Database object {0} cannot be used for editing.
@@ -298,3 +302,5 @@ TestLocalizationConstant = EN_LOCALIZATION
 # Utilities
 
 SqlScriptFormatterDecimalMissingPrecision = Decimal column is missing numeric precision or numeric scale
+
+SqlScriptFormatterMultipartDecodeFail = Multipart identifier is incorrectly formatted