ModelCardDatabase can retrieve a card by ID

Added numerous Send argument classes:
- ConversionResult (incomplete)
- SendError
- SendObject
- SendViaBrowserArgs (incomplete)
Send method looks up model card and account details, constructs send arguments
AccountDatabase can find an account by ID or server URL
Added DetachedMemoryStore

SpeckleConnector/Connector/Database/ModelCardDatabase.cpp

@@ -71,6 +71,16 @@ ModelCardDatabase::ModelCardDatabase() {
 ModelCardDatabase::~ModelCardDatabase() {}
 
 
+/*--------------------------------------------------------------------
+	Get a specified card from the database
+ 
+	return: The requested card (nullptr on failure)
+  --------------------------------------------------------------------*/
+ModelCard::Unique ModelCardDatabase::getCard(const speckle::utility::String& cardID) const {
+	return m_store->getObject(cardID);
+} //ModelCardDatabase::getCard
+
+
 /*--------------------------------------------------------------------
 	Get all model cards