doc/bugs.txt: Add description of symlink bug in browser.
doc/bugs.txt: Remove old bug which is likely invalid at this point.
Reorganize hfscommon inheritance hierarchy, introducing keyed nodes.

Keyed nodes (CommonHFSKeyedNode) is a generalization of all nodes that
have records indexed by keys (CommonHFSKeyedRecord).

In practice this means leaf nodes and index nodes, which can now be
treated equally by certain search functions in BTreeFile.

CommonBTIndexNode is removed since CommonBTKeyedNode replaces it.
Generalize findLEChildKeys in CatalogFile into findLEKeys in BTreeFile.
build.xml: Rename target 'libhfs' to 'hfs-jfuse_libhfs'.

The name 'libhfs' implies that the library is more generic than it
really is.

Also add manifest for created .jar file for dependency resolution
purposes.
build.xml: Slim down hfs-jfuse_libhfs to only include necessary classes.
build.xml: Fix line width 80 overflow in help message.
build.xml: Fix case of catacombaeframework directory javadoc reference.

The standard directory name is nowadays in lowercase.
Retire [BTree|Catalog|ExtentsOverflow]Operations.

All HFS implemenations (HFS, HFS+, HFSX) need to implement all these, so
it doesn't make sense to have separate interfaces just for helper
operations that everyone needs to implement anyway.
It also adds complexity and limitations when creating the volume object,
since the operations object cannot reference the volume object before it
has been fully initialized.

The functions are now instead moved into HFSVolume as abstract methods.
Consolidate duplicated code from subclasses in BTreeFile.

The different BTreeFile subclasses CatalogFile, ExtentsOverflowFile and
AttributesFile contained duplicated code for reading nodes, getting the
root node, etc.

This commit consolidates that code in BTreeFile.
Add support for reading HFS+ custom attributes from the attributes file.

The support is implemented all the way to the file system handler
package (org.catacombae.storage.fs.hfscommon), but the GUI/tools do not
yet support extracting attributes.
HFSExplorer.java: Replace copyright symbol with '(C)' in console output.

Few terminals are capable of displaying this symbol properly (Unicode
support should be universal at this point but in reality the fonts often
lack support).
Add capability reporting to FileSystemHandler.

We shouldn't need to have access to its factory in order to determine
what capabilities a file system supports.
Consolidate all sources in directory 'src'.

Previously we had a source directory in the project root for each type
of source file. We now move these into their own subdirectories within
'src', making the project root cleaner.