Exchange simulator: switch from epoll to libevent

In order to support market simulator on various
platforms a cross-platform techniques should be
used. In particular, epoll is not present on such
a platform as Darwin but libevent fills the gap.

Signed-off-by: Marat Stanichenko <mstanichenko@gmail.com>
Add compatibility header to 'forts'

'forts' uses 'clock_gettime' which is provided by the compatibility
layer on Darwin.

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Include 'libgen.h' in 'market'

'basename' is not declared on Darwin unless 'libgen.h' is included.

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Merge pull request #42 from mstanichenko/libevent

Exchange simulator: switch from epoll to libevent
Merge pull request #43 from jvirtanen/fixes/darwin

Improve Darwin support