====== Caching ======

We need to cache both the index and the linking structure of a notebook in order to be able to do quick lookups. So far this is done by a simple text file.

Disadvantage is that this scales badly (although no complaints so far - probably we are saved by the kernel file system layer caching this file in memory). Another issue is that the code separation is messy because I tried to optimize for this plain text file.

The Good Way® to do this would be to pull in SQLite. There is a good CPAN module for this using the DBI interface and for windows ActiveState ships this module as part of the core package (albeit an older version).

Extra advantage is that apart from the default tables with index and links special storage backends like e.g. the [[AlbumPlugin]] or the [[TagsPlugin]] could define their own tables with additional properties that might need caching.
