Key classes missing javadoc

[syntaxi]

This module is missing javadoc in a number of classes. There are some key ones listed below.

• PathFamily.java
• BlockMappingComponent.java
• PathComponent.java
• PathDescriptorComponent.java
• SegmentEntityComponent.java
• SegmentCacheSystem.java
• SegmentMapping.java
• SegmentSystem.java
• SegmentCacheSystem.java
• OnExitSegment.java
• OnVisitSegment.java

[Meta-Maxim]

Resolved SegmentEntityComponent.java with #5

[eviltak]

Documented the Segment interface via #10. It's not in the above list because the list is outdated after the latest SegmentedPaths rework.