added tests for the same column name in multiple tables; fixes #85 and fixes #81
tests for correct prepared statements quoting (integer, boolean, ...); fixed #82
removed commented out code
unifying travis with vagrant + fixing vagrant
added unsupported boolean for Firebird, DB2 and SQLite
tests for re-running logged SQLs
hsqldb updated from 2.3.0 to 2.3.1
updates in tests of the same named columns in 2 tables