Move doc string parsing logic from rebuildParsers.php and
String_::parseDocString() into ParserAbstract. This stuff is
going to get complicated now.
For now only implement the validation of the indentation on the
end label.
Scalar\String_ and Scalar\Encapsed now have an additional "kind"
attribute, which may be one of:
* String_::KIND_SINGLE_QUOTED
* String_::KIND_DOUBLE_QUOTED
* String_::KIND_NOWDOC
* String_::KIND_HEREDOC
Additionally, if the string kind is one of the latter two, an
attribute "docLabel" is provided, which contains the doc string
label (STR in <<<STR) that was originally used.
The pretty printer will try to take the original kind of the string,
as well as the used doc string label into account.
Kind specifies whether the number was formatted as decimal, octal,
binary or hex. The pretty printer reproduces the number kind (but
not necessarily the exact formatting).
Instead of storing subnodes in a subNodes dictionary, they are
now stored as simple properties. This requires declarating the
properties, assigning them in the constructor, overriding
the getSubNodeNames() method and passing NULL to the first argument
of the NodeAbstract constructor.
[Deprecated: It's still possible to use the old mode of operation
for custom nodes by passing an array of subnodes to the constructor.]
The only behavior difference this should cause is that getSubNodeNames()
will always return the original subnode names and skip any additional
properties that were dynamically added. E.g. this means that the
"namespacedName" node added by the NameResolver visitor is not treated
as a subnode, but as a dynamic property instead.
This change improves performance and memory usage.
