ADD: User authentication

* User Authentication Implementation
* Rename file to conform to fileformat `sqlite3_*_omit.go`
* Updated sqlite3-binding.* with new upgrade tool
* Add: callbackRetNil required for error type return because of adding `RegisterFunc`s directly on the connection.
* Add: TestCreateAuthDatabase

sqlite3-binding.h

@@ -11179,4 +11179,100 @@ struct fts5_api {
 #else // USE_LIBSQLITE3
  // If users really want to link against the system sqlite3 we
 // need to make this file a noop.
- #endif
+ #endif
+/*
+** 2014-09-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the application interface definitions for the
+** user-authentication extension feature.
+**
+** To compile with the user-authentication feature, append this file to
+** end of an SQLite amalgamation header file ("sqlite3.h"), then add
+** the SQLITE_USER_AUTHENTICATION compile-time option.  See the
+** user-auth.txt file in the same source directory as this file for
+** additional information.
+*/
+#ifdef SQLITE_USER_AUTHENTICATION
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+** If a database contains the SQLITE_USER table, then the
+** sqlite3_user_authenticate() interface must be invoked with an
+** appropriate username and password prior to enable read and write
+** access to the database.
+**
+** Return SQLITE_OK on success or SQLITE_ERROR if the username/password
+** combination is incorrect or unknown.
+**
+** If the SQLITE_USER table is not present in the database file, then
+** this interface is a harmless no-op returnning SQLITE_OK.
+*/
+int sqlite3_user_authenticate(
+  sqlite3 *db,           /* The database connection */
+  const char *zUsername, /* Username */
+  const char *aPW,       /* Password or credentials */
+  int nPW                /* Number of bytes in aPW[] */
+);
+
+/*
+** The sqlite3_user_add() interface can be used (by an admin user only)
+** to create a new user.  When called on a no-authentication-required
+** database, this routine converts the database into an authentication-
+** required database, automatically makes the added user an
+** administrator, and logs in the current connection as that user.
+** The sqlite3_user_add() interface only works for the "main" database, not
+** for any ATTACH-ed databases.  Any call to sqlite3_user_add() by a
+** non-admin user results in an error.
+*/
+int sqlite3_user_add(
+  sqlite3 *db,           /* Database connection */
+  const char *zUsername, /* Username to be added */
+  const char *aPW,       /* Password or credentials */
+  int nPW,               /* Number of bytes in aPW[] */
+  int isAdmin            /* True to give new user admin privilege */
+);
+
+/*
+** The sqlite3_user_change() interface can be used to change a users
+** login credentials or admin privilege.  Any user can change their own
+** login credentials.  Only an admin user can change another users login
+** credentials or admin privilege setting.  No user may change their own 
+** admin privilege setting.
+*/
+int sqlite3_user_change(
+  sqlite3 *db,           /* Database connection */
+  const char *zUsername, /* Username to change */
+  const char *aPW,       /* New password or credentials */
+  int nPW,               /* Number of bytes in aPW[] */
+  int isAdmin            /* Modified admin privilege for the user */
+);
+
+/*
+** The sqlite3_user_delete() interface can be used (by an admin user only)
+** to delete a user.  The currently logged-in user cannot be deleted,
+** which guarantees that there is always an admin user and hence that
+** the database cannot be converted into a no-authentication-required
+** database.
+*/
+int sqlite3_user_delete(
+  sqlite3 *db,           /* Database connection */
+  const char *zUsername  /* Username to remove */
+);
+
+#ifdef __cplusplus
+}  /* end of the 'extern "C"' block */
+#endif
+
+#endif /* SQLITE_USER_AUTHENTICATION */