Tidied up utilities:
  - Removed UUIDUtil.class; the class offered only one used method
somewhere that is not a part of the Bukkit API.
  - Removed MathUtil.class; only the square(double, double) function was
used, which is already a part of the ever so elusive Math.class that is
part of the JDK environment.
  - Removed the boolean parameter check in StringUtils#trimByRegex()
  - Updated all files accordingly.