When loading a blend file from one computer to another, there are
situations where the fonts in a scene don't get loaded properly. This
is because the location of the vector fonts' filepaths might not match
on different systems. Its not a big deal to manually update this by
reselecting the font when working on a scene, but it can get
troublesome when using netrender or some other distributed rendering
system where the filepaths might differ (i.e. /Users/username/... and
/home/username between Mac and Linux)

Steps to recreate:

* Create a blend file with a text object in it and save it to a
location, for example along side a truetype font

* Under the object data panel, in the font section, browse and select
the truetype font that resides next to the newly created blend file

* In the outliner, select datablocks and drill down to the font object
(under Vector Fonts), the filepath attribute contains an absolute
path on the disk

I tried to edit and make the filepath relative using the Python API,
but the property was read-only. Maybe a 'Use relative paths' option
would be helpful when browsing font files?

Tested on:

* blender-2.55.0 r32738 on a MacBookAir3,1, Intel Core 2 Duo, NVIDIA GeForce 320M, Mac OS X 10.6.5
* blender-2.55.1 r33889 on a Thinkpad Edge, Intel Core 2 Duo, Intel GMA 4500MHD, Ubuntu Linux 10.10