Fixed man page for CURVE key options

Add new tests to CMakeLists.txt

Cleaned up the code

- removed unnecessary malloc
- spaces, not tabs to indent
- renamed control states to be more logical
- renamed SUSPEND to PAUSE, feels more accurate
- fixed indentation, which was off in places

add proxy control flow and test

Use consistant integer type in raw_decoder

Update zmq_msg_init_data.txt

Temporary workaround for broken libsodium install

Load identity message to decoder at start

Fixed out-of-source build

Rename engine's methods to improve code readability

Fixed doc for IDENTITY socket option

Reverted use of enums for zmq.h constants (too painful for binding authors)

This reverts commit d4bb6d69.

This reverts commit e7804c50.

Updated NEWS for 4.0.1 release

Typo in type name "emTPy_slots_t"

https://zeromq.jira.com/browse/LIBZMQ-565

Add documentation on Linux ipc abstract namespace support and a bug fix.

Abstract socket pathnames must have a NULL character in the first
position, but the second character must also be checked to differentiate
an abstract name from the empty string.  The address length must also
indicate the length of the pathname because the kernel uses the entire
address as the name, including NULL characters.  ZMQ uses
NULL-terminated strings for the address, so the abstract address length
is the length of the string following the initial NULL byte plus 3; two
bytes for the address family and one for the initial NULL character.