JavaDoc some Util methods and organize exceptions
Merge branch 'pr/5'

Conflicts:
	src/main/java/com/dsh105/nexus/command/module/BuildCommand.java
	src/main/java/com/dsh105/nexus/command/module/CICommand.java
	src/main/java/com/dsh105/nexus/hook/jenkins/Jenkins.java
	src/main/java/com/dsh105/nexus/util/StringUtil.java