Added getters for Serializer options;
Swapped the indent and indent string options at Serializer's constructor;
Renamed Serializer::setIndentFirstLine() to setIsFirstLineIndented() in accordance with the getter (PHPMD fix);
Line length is now ACTUALLY line length, i.e. it takes the indentation into account, and is applied to tags as well;
Fixed ReturnTag::setContent() to set "types" to NULL;
A lot of doc and CS fixes at Serializer.php.