GYP: Stronger MSVS Version Autodetection; VC2010 Express support

GYP: Stronger MSVS Version Autodetection; VC2010 Express support 

1) Cleans up reg.exe launching by putting the logic into a single function. Also:
1a) Attempts Sysnative to bypass WoW directory redirection on 64-bit machines using 32-bit python (default with depot_tools); if that fails it falls back to the normal System32 reg.exe. Sysnative is available on Vista and up; XP and 2003 have a KB patch available (KB 942589 - http://support.microsoft.com/kb/942589/en-us).
 
2) Changes _CreateVersion() in MSVSVersion.py: 
2a) Adds "2010e" MSVS_VERSION detection, passes it to the gyp files, and sets flat_sln to True as VC2010 express does not appear to support non-flat similar to previous express versions.
 
3) Changes _DetectVisualStudioVersions() in MSVSVersion.py: 
3a) Modifies the newer (2010+) DevDiv detection method to scan for the express key.
3b) Detect 32-bit versions of MSVS through the Wow6432Node registry key. 
3c) Detect MSVS Express versions, currently only 32-bit but checks both the normal and WoW locations in case of a (now more common) 64-bit machine.
 
BUG=http://code.google.com/p/gyp/issues/detail?id=186 
TEST=Make sure it auto-detects the proper MSVS version as well as express versions; in the case of 2010 express, passes "2010e" as MSVS_VERSION and generates correct project/solution files. If using 32-bit python on a 64-bit machine ensure it correctly bypasses WoW directory redirection and uses C:\Windows\System32 through the virtual directory c:\Windows\Sysnative (32-bit python is the default included with depot_tools).

[RN, 2011-03-27 15:43:10]

Updated description a bit to explain the code change(s) more.

[bradn, 2011-03-27 16:30:18]

LGTM

I'll endeavor to land it for you soon?

[RN, 2011-03-27 21:48:24]

On 2011/03/27 16:30:18, bradn wrote:
> LGTM
> 
> I'll endeavor to land it for you soon?

I'm just a random contributor; since it looks good to you if you could land it
for me that would be great - thanks.

[RN, 2011-03-30 07:02:43]

Updated for VC2010 express

[RN, 2011-03-30 07:02:43]

Updated for VC2010 express

[RN, 2011-03-30 07:10:50]

Killed whitespace; take your time with this if you want. mini_installer on
Chromium compiles on VC2010 express with a couple non-GYP tweaks correctly with
this.

[Mark Mentovai, 2011-04-06 21:22:19]

Brad, you gave LGTM and said you’d land this soon. Since then, Ryan has made
changes. What’s up with this?

[RN, 2011-04-06 21:34:06]

It's probably my fault for adding in a couple more related fixes/tweaks a few
days later. I haven't heard from Brad on whether he wants me to split it up or
not, though I'm assuming that's the case since I haven't heard anything for a
week.

 On 2011/04/06 21:22:19, Mark Mentovai wrote:

[RN, 2011-04-15 12:33:01]

Another week.... did some more tweaks to tweaks and added in sysnative directory
bypassing for those on 64-bit machines use the 64-bit version of reg.exe and not
the redirected 32-bit version that cannot correctly query 64-bit registry keys.
The default 32-bit version of python that comes with depot_tools, so more
out-of-the-box experience there.

Also updated the copyright and added myself to AUTHORS as required by my other
Chromium CLs.