[Qgis-developer] OSX build instructions update

[William Kyngesburye]

I took the liberty of updating the INSTALL build instructions for OSX  
in trunk.  INSTALL should probably be updated for other systems, as  
there are some old version references (both dependencies, and QGIS  
itself).  Should INSTALL be updated in release 1.1 before release?

Some notes on my OSX changes:

I removed most explicit version references for dependencies.

I didn't touch the subversion section, since I'm working on Leopard,  
which includes svn.

I didn't touch the Qgis source download section.  There are old QGIS  
version references for checking out source, but I wasn't sure how to  
clean it up.  Maybe we should have some tarball download instructions  
also?  And a generic svn checkout example?

-----
William Kyngesburye <kyngchaos*at*kyngchaos*dot*com>
http://www.kyngchaos.com/

"This is a question about the past, is it? ... How can I tell that the  
past isn't a fiction designed to account for the discrepancy between  
my immediate physical sensations and my state of mind?"

- The Ruler of the Universe