Improve EnvironmentVariableTool to VariableTool: can do any sort of variable replacement now.
Make it a real variable tool, working on a variable source.
Dismantle BaseWikiPage: get rid of methods getNormalChildren and getNormalChildPage.
Technically speaking, the only pages that can have symlinks are FileSystemPages. So only those pages need to resolve symlinks.
move symbolicPageFactory to FileSystemPage.
Clean up in FileSystemPage
Let FileSystemPage no longer depend on the other page types.
The road to extensibility.
Remove autoCommit property from FileSystemPage. It has only been used in tests.
Use getChildPage to implement hasChildPage (instead of addChildPage, which adds a new page).
Update release notes.