Improve ProcessFunctionTimers example (Chapter 6)

Fixed timer deletion bug in CoProcessFunctionTimers example (Chapter 6)

Update README.md

Improve KeyedTransformations example

Enable first strategy to handle late data.

Improve specification of state types.

Improve Chapter 7 examples.

rename variable readings

Reduce dependencies and size of application JAR file.

Add runtime-web to IntelliJ dependencies to start WebUI from IntelliJ jobs.

Increase version to 1.0 and update pom.xml

Update Flink dependencies to 1.7.1 and Scala 2.12

Improve SideOutput example.

Use deleteTimer() in Chapter 6 examples.

Use deleteTimer() in Chaper 7 examples.