PostgreSQL fixes

This covers several fixes to (re-)enable support for pgsql database in master branch, which has been broken since upgrade to unpatched ADOdb 5.11 several years ago. With these, PostgreSQL should now be operational: 

- Correct handling for booleans, including fix of installer/upgrade process to convert pre 1.1.0 instances SMALLINT columns to BOOLEAN
- *Finally* fixing the broken Travis builds. This required new DB API calls to push/pop the parameter count to a stack, to enable concurrent build of multiple queries (required as pgsql uses positional parameters). Initial implementation 124f79e516a4264df1c43ec4494f18aebd65bc14 was procedural, then I moved this to a simple class in d09d5ada7cde90e2d4be7400a0dafd698b8e5f61
- ADOdb update to latest development head (includes a required fix to `ADODB_postgres64->Param()` )

Includes .travis.yml changes to stop ignoring pgsql build failures.