Ingres support for Flyway. It also has several other fixes I needed.

Ingres support has been tested and it works.

I also added a quick-and-dirty support for a typical Linux environment in relation to Maven and Ant installation paths, because Maven doesn't run correctly if M2_HOME is set like given in the tutorial and it has been installed with apt-get (or yum, or similar) to /usr/bin.

Also added support for skipping the module execution (new parameter "skip", very standard), because that is a must-have in a multi-module project.

I also updated the JDBC client versions to the most current ones in the pom.xml.