Trailing whitespaces, code formatting, detabify

A major cleanup of trailing whitespaces and tabs in codeGen/
directory. I also adjusted code formatting in some places.
Cleanup StgCmm pass

This cleanup includes:
  * removing dead code. This includes forkStatics function,
    which was in fact one big noop, and global bindings in
    CgInfoDownwards,
  * converting functions that used FCode monad only to
    access DynFlags into functions that take DynFlags
    as a parameter and don't work in a monad,
  * addBindC function is now smarter. It extracts Id from
    CgIdInfo passed to it in the same way addBindsC does.
    Previously this was done at every call site, which was
    redundant.
Remove unused module

This commit removes module StgCmmGran which has only no-op functions.
According to comments in the module, it was used by GpH, but GpH
project seems to be dead for a couple of years now.
Merge cgTailCall and cgLneJump into one function

Previosly logic of these functions was sth like this:

  cgIdApp x = case x of
                A -> cgLneJump x
                _ -> cgTailCall x

  cgTailCall x = case x of
                   B -> ...
                   C -> ...
                   _ -> ...

After merging there is no nesting of cases:

  cgIdApp x = case x of
                A -> -- body of cgLneJump
                B -> ...
                C -> ...
                _ -> ...
Comments only
Added bullet in release notes about roles.
Added paragraph to user's guide about Nominal role for Set
Detabify

I missed that file yesterday when I was cleaning up codeGen/ directory.