Process the -C option before running RUN_AFTER_FLAGS tools.

This brings the flag more inline with its description: "change to
DIR before doing anything else".

The use case is to make it possible to use -C together with -t msvc.
When debugging Windows builds, it's handy to be able to copy-paste
the commands from "ninja -v" and make them run in the correct
directory by adding this flag.
wip for console pool on windows
win console wip: enable test
win console wip: ctrl-c should reach commands running in console pools
vim syntax: Correctly highlight $$a as ($$)a instead of $($a).
win console wip: resolve FIXME
win console wip: Fix comments based on review feedback.
Merge pull request #764 from nico/winconsole

Implement pool=console support on Windows.
CleanTest cleanups:
* $in only makes sense on rules, not edges (see issue #687)
* Remove unneccesary clear() line at end of test
Merge pull request #766 from nico/cleanup

CleanTest cleanups:
Make "depfile=$out.d" work if $out contains escaped characters, rspfile too.

Fixes #730.  This has always been broken, but due to #690 more paths are now
escaped (e.g. paths containing + characters, like file.c++).  Also see
discussion in #689.

The approach is to give EdgeEnv an enum deciding on whether or not to escape
file names, and provide functions that evaluate depfile and rspfile with that
set that to kNoEscape.  (depfile=$out.d doesn't make sense on edges with
multiple outputs.)

This should be relatively safe, as $in and $out can't be used on edges, only
on rules (#687).
reword manual for depfile/rspfile escaping change
Merge pull request #767 from nico/esc_deprspfile

Make "depfile=$out.d" work if $out contains escaped characters, rspfile ...
Merge pull request #768 from nico/vimsyn

vim syntax: Correctly highlight $$a as ($$)a instead of $($a).
Allow + in filenames without escaping

Due to #690, file.c++ used to be escaped. + seems as safe as -, so allow
it to not be escaped, to keep compile command lines with a fairly common
extension slightly cleaner.
Merge pull request #769 from nico/plus

Allow + in filenames without escaping
Use unversioned gnukfreebsd platform.
Merge pull request #770 from debfx/master

Use unversioned gnukfreebsd platform.
Version 1.4 of the vim syntax file was merged.

See https://code.google.com/p/vim/source/detail?r=92751673cc37c9ef4d1ad1ac4d42d36faa67f88f
create a slightly nicer build.ninja on windows