Revert "Revert unit tests name modification"

This reverts commit 47d1b68933bdc85aed1c90a2fd8e26bb595f9bb7.
Revert "SONAR-3976 Introduce the concept of plugin group"

This reverts commit e1bccb1b2268d6b2bd809c6699e4e96f832c513d.
Revert "Set sonar-update-center-common version to 1.5-SNAPSHOT"

This reverts commit 9d7ba3981d3bcd1b2eaf7681adb62f04bafa6286.