Support to JasperReports 6.20.1 to 6.20.5

Removed Webwork and Struts2 support
changes to doc site (github pages)

fix for #118

update changes.xml, bumped version to 5.3.7

update changes.xml, version bump 5.3.6

Bumping some library versions due to vulnerabilities (2)

DJ supports JR 6.17.0

DJ supports JR 6.13.0

Fix on group anchor name when expression is not a string

changes.xml for DJ version 5.3.0

java 8 needed.

Works with JasperReport 6.6.0 to 6.7.1

commented unsupported xlint for java 7