Add StringUtil lib, fix some bugs into controllers
Delete folder samples
Merge branch 'master' into roma
liquibase work,
hello
Add safe delete support
fix bugs
new dump and safe delete
Modal windows add animate, remake cron,
Create folder for new liquibase changeset, delete a few css files
Merge branch 'master' into roma

Conflicts:
	SSEL/src/main/java/com/softserve/dao/CourseSchedulerDao.java
	SSEL/src/main/java/com/softserve/dao/impl/CourseSchedulerDaoImpl.java
	SSEL/src/main/java/com/softserve/entity/Group.java
	SSEL/src/main/java/com/softserve/service/CourseSchedulerService.java
	SSEL/src/main/java/com/softserve/service/impl/CourseSchedulerServiceImpl.java
Code refactoring, add new changeset to liquibase 3.0
merging vetall1 branch with master