Contrast-Finder v0.9.1

Upgrade-o-meter: just replace the .war file and restart Tomcat
Thanks to @davidjr82 (PR #158)

Security:

• #152 - Upgraded SpringFramework (4.3.17 instead of 4.3.16)
• #160 - Upgraded spring--security (4.2.6 instead of 4.2.5)

Improvement:

• #158 - Update Spanish i18n file and title attribute in language menu

Configuration:

• #159 - Changed default docker image: ubuntu-18.04_tomcat-8.5 instead of ubuntu-16.04_tomcat-7

Task:

• Delete old DockerFiles