This commit removes the support for the maxheap configuration flag since
now the heap memory is allocated on demand and not on startup in one single
large allocation.

Using the system paging file to implement COW.

Moved important comments regarding the QFork architecture at the top of
the file. Formatted comments and code. Changed SIZE_T to size_t for
consitency.

This is part of a set of changes in order to make easier to add support
for jemalloc and remove the memory mapped file.

A previous commit that fixed a socketstate leak exposed another existing bug:
if FDAPI_AcceptEx() fails the socketstate is accessed after the socket has
already been closed and the socketstate memory has been released, causing
a heap corruption exception .

[Fix] Improved error handlingin WSIOCP_Listen().

On Windows two temp files are created during an AOF rewrite.
Both files were left behind in some error cases.
There is only one case for which we want to keep one of the temp file since
the user may need it.

[Fix] Close the file handle after truncating a file.

[Fix] Windows portability: explicit type casting.
[Cleanup] Code refactoring. Comments. Changed functions prefix to match
the functions type.

[Test] Added log.txt to gitignore for sentinel tests.
[Test] Added log.txt to gitignore for cluster tests.
[Test] Speed up creation of redis-server instances.
[Test] Replaced comment with windows-specific "if" condition.

On Windows the tclsh scripts sometime takes longer to complete, causing some
tests to fail.

On Windows, genClientPeerId used to return the hardcoded string "MASTER:0"
instead of the ip:port value, it is now fixed so the windows-only case in
the test is not needed anymore.

To workaround the problem, the socket address storage is saved in the RFDMap
socket info structure upon the socket creation.

This is only an initial refactoring of the headers, the final goal is to
have hiredis completely independent from the QFork code in order to build
it as a standalone lib that can be used in other projects.

[Cleanup] Cleaned up code.

[Setup] Updated version number.