Rewrite electricity-logger to use an sqlite3 database

include/migrator/migrations.hpp

@@ -0,0 +1,9 @@
+#pragma once
+#include <string>
+
+namespace Migrations
+{
+    int EpochToDateTime(std::string const & sourceDatabase, std::string const & destinationDatabase);
+
+    int UpdateSummaryTable(std::string const & sourceDatabase, std::string const & destinationDatabase);
+}

include/migrator/transaction.hpp

@@ -0,0 +1,24 @@
+#pragma once
+#include <sqlite3.h>
+#include <sstream>
+
+class Transaction {
+private:
+    sqlite3 * const destination;
+    unsigned queryCount;
+    std::stringstream queryStream;
+
+    void Reset();
+
+public:
+    void AddStatement(std::string const & statement);
+
+    unsigned StatementCount() const;
+
+    // Runs the statements inserted as a single transaction
+    // Returns a SQLite status code (0 = OK) and then resets
+    // to a new transaction
+    int Execute();
+
+    Transaction(sqlite3 * const databaseToInsertIn);
+};