doc: cleanup - remove the 4 stage descriptions.
Avoid exceptions during debugging, fix predicates of STC instructions

* Do not peek into memory while stalling for --debug-fmt=instr to prevent exceptions.
* Do not modify $ss and $st if STC instruction is skipped to prevent hazards.
pasim: correctly update values of $ss and $st when stalling in STC ops.
chisel: Add type information to OCP port for caches.
mcache: changed to single fifo mcache instead of generic version
chisel: Shorten critical path in fetch unit.
doc: Various comments on ISA revision suggestsions

* Comments on special registers for return info, branch addressing and dual issue.
* Suggested adding an offset to brcf indirect.
Merge branch 'master' of github.com:t-crest/patmos
doc: Comment on Stefan's comments.
doc: comments on control flow instruction changes
doc: Comments on comments on proposed instruction changes
chisel: small rename/refactor at the stalling generation
Merge branch 'master' of github.com:t-crest/patmos
chisel: consistent names for registers
modelsim: fix signal names
doc: Moved comment about memory op issuing to a subsection on its own
chisel: Cleaner registering in timer I/O module.
chisel: Remove critical path in fetch unit.
chisel: Improvements for single-issue version of Patmos.
chisel: Set default frequency to 80 MHz.