* Introduce new package attribute B_HPKG_ATTRIBUTE_ID_PACKAGE (valid
only in a repository file) to group the attributes belonging to a
package.
* BRepositoryContentHandler:
- No longer derive from BPackageContentHandler.
- Add hooks HandlePackage() and HandlePackageDone() that bracket the
attributes for a package. This is more explicit and robust than
handlers having to guess when one package ended and the next began.
* BRepositoryCache: Make use of BPackageInfoContentHandler. No need to
duplicate the code for reading a package info from package info
attributes.
* For all identifiers: Rename global settings file to global writable
file. We want to use the respective attribute also for other writable
files, not only settings files.
* User settings file/global writable file info/attribute: Add
isDirectory property/child attribute. This allows declaring global/
user settings directories associated with the package.
... <package/hpkg/PackageAttributes.h>, which also defines other
properties (name and type) for each attribute. It does so via a macro
that the caller can define to generate whatever code is desired.
