Rework the TAP creation documentation.

 - Try to use "TAP" not "tap" everywhere; it's an acronym.

 - Update the associated "target config files" section:
     * reference the "TAP Creation" chapter for details
     * simplify:  reference interesting multi-tap config files
     * let's not forget CPU configuration (*before* workspace setup)
     * streamline it a bit
     * move that workspace-vs-mmu issue to a better location

 - Clean up TAP creation doc mess
     * switch to @deffn
     * (re)organize the remaining stuff
     * reference the "Config File Guidelines" chapter

 - Tweak the "Target Configuration" chapter
     * rename as "CPU configuration"; unconfuse vs. target/*.cfg
     * bring out that it's not just there for GDB
     * move TAP events to the TAP chapter, where they belong (bugfix)


git-svn-id: svn://svn.berlios.de/openocd/trunk@2013 b42882b7-edfa-0310-969c-e2dbd0fdcd60