windows: fix perfctr crash on XP and 2003

Some performance counter related functions are not available on Windows
XP and Windows Server 2003, which caused node to call a NULL pointer.

Closes #4462
Closes #4511
windows: improve Visual Studio Express build support

* Moved generated files to a clearer directory.
* Improved detection logic for ctrpp.exe tool.

Closes #4482
REPL: fix floating point number parsing

In JS, the expression ".1" is a floating point number.  Issue 4268 concerns the
REPL interpreting floating point numbers that lead with a "." as keywords.  The
original bugfix worked for this specific case but not for the general case:

    var x = [
        .1,
        .2,
        .3
    ];

The attached change and test (`.1+.1` should be `.2`) fix the bug.

Closes #4513.
v8: update to 3.15.11.5
object_wrap: add missing HandleScope

by Sven Panne's suggestion, see [0] for details.

[0]: https://code.google.com/p/v8/issues/detail?id=2468
v8: remove optimization switches

Remove compiler switches from $(TOPLEVEL)/deps/v8/build/common.gypi,
we set them globally in $(TOPLEVEL)/common.gypi.

Commit 7b4d95a introduced the switches again, resulting in V8 getting
built without any optimizations.

This commit is essentially a rehash of commit 4b8629d.
fs: pool size coincide with ReadStream bufferSize

pool size of file reading in ReadableStream can be adjustable
with a bufferSize option.
fs: remove unused default option in WriteStream

No bufferSize option is used in stream.Writable and fs.WriteStream.
buffer: floating point improvements

Improvements:
* floating point operations are approx 3x's faster
* NaN/Infinity assignation more closely follows d8's implementation
* all read/write on floating point now done in C, so no more need for
  lib/buffer_ieee754.js