ConfigFile parses simple configuration files and store its values in an
anonymous hash reference. The syntax of the configuration file is quite
simple:

1. This is a comment VALUE_ONE = foo VALUE_TWO = $VALUE_ONE/bar
VALUE_THREE = The value contains a \# (hash). # This is a comment.
COMPOSED_VALUE[one] = The first component of a clustered value
COMPOSED_VALUE[two] = The second component of a clustered value