As per suggestion by Pieter Hintjens. Also update wording in
zmq_ctx_set manual a bit.

The new options allows querying the maximum allowed number of sockets.
This is system dependent and cannot be encoded in the include file as a
preprocessor macro: for ZMQ_USE_SELECT, this depends on the FD_SETSIZE
macro at time of library compilation, not at time of include file use.

Fixes #872

Terminate context in a child process of fork() to replace file descriptors to not interfere with parent process's context

Ignored more MSVC intermmediate files.

Copyrights had become ads for Sustrik's corporate sponsors, going against the original
agreement to share copyrights with the community (that agreement was: one line stating
iMatix copyright + one reference to AUTHORS file). The proliferation of corporate ads
is also unfair to the many individual authors. I've removed ALL corporate title from
the source files so the copyright statements can now be centralized in AUTHORS and
source files can be properly updated on an annual basis.

Fixed 7 MSVC2008 Compiler Warning (level 3) C4800: 'const int' : forcing value to bool 'true' or 'false' (performance warning)

- added explicit test "(xxx != 0)" to get a "bool" value out of the "int" expression
- see the MSDN recommandation http://msdn.microsoft.com/en-us/library/b6801kcy(v=vs.90).aspx

Significantly reworked the monitoring infrastructure with a more granular per socket API and to play well with monitoring endpoints in application threads

Compile was failing on the monitor_event function function due to the
va_start params being switched.

There are three versions of monitor_event(), all taking
variadic arguments. The original code just has the first one
creating a va_list and passing that va_list variadically to
the second one... which creates a new va_list and passes it
variadically to the third one... and of course everything
blows up when we try to pull a non-va_list argument off the
stack.

The correct approach matches the C standard library's use
of printf/vprintf, scanf/vscanf, and so on. Once you make
a va_list, you must pass it only to functions which expect
a va_list parameter.

* corrects whitespace errors
* fixes spelling errors in comments
* prefers #ifdef to #if defined

* Implemented new ctx API (_new, _destroy, _get, _set)
* Removed 'typesafe' macros from zmq.h
* Added support for MAX_SOCKETS (was tied into change for #337)
* Created new man pages

- anonymous contributor

This reverts commit 7b7d4042.

We use a distinct context initialisation function to specify
all sockets derived therefrom will be thread safe.

However the inheritance is done exclusively in the C interface.
This is not really correct, but it is chosen to minimise
interference with the existing C++ code, including any
construct or other calls within the C++ code base.
Semantically the C++ code should be unchanged,
physically some data structures and extra methods are
provided by they're only used from the C binding.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>