Support local linking of fragments

[corvus-ch]

Using version 6.18, I have two options to link two fragments with each other. One is by adding a relationship an the other is to insert a link into the fragment text. If I do the later, I only can add absolute links. While this is fine for linking to external resources, this might become a problem for linking to local resources.

Troubles might be when you are forced to switch switch port or if you move your Piggydb from your local machine to a sever wich changes the url. In that case you will end up with broken links in your db.

I request that linking text also supports linking to fragments as well as tags.

Example:

[42 This links to fragment with the id 42]
[Inceptos This links to the tag named Inceptos]

[marubinotto]

You can create an internal link by writing:

[fragment:42 This links to fragment with the id 42]

About fragment links for more detail, please refer to the wiki help.