fix #3271 (closed)
This removes the LiteSQL dependency, but we keep the sqlite3 dependency.
The build process is much simpler, because everything is just pure C++ (with a lot of templates!): we don’t need any external compiler to process some XML or hpp.
This code will not modify the database created by the previous versions (using LiteSQL).
It will create an compatible schema, if the schema doesn’t exist, otherwise it will do nothing.
The code to upgrade the schema to future versions (add columns, etc) is not included. We will add that later, when needed.
Default value should not count as “non-empty” in the get_first_non_empty() function
Fix the memory leaks with the sqlite_stmt objects (and maybe some others).