lib: Simplify buffer_sum()

Use buffer_sum_range() for buffer_sum() to simplify it.  A nice
side-effect of the simplification is increased encoding speed:

  Before:

  [penberg@localhost libtrading]$ ./tools/fix/fix_perf 10000000
  encode     10000000 0.214934 µs/message

  After:

  [penberg@localhost libtrading]$ ./tools/fix/fix_perf 10000000
  encode     10000000 0.186174 µs/message

Signed-off-by: Pekka Enberg <penberg@iki.fi>
Use $(PYTHON) for 'fixdialectc'

Use $(PYTHON) instead of the current Python for running 'fixdialectc'.
This makes it possible to install the 'fixdialectc' dependencies into
a Python virtual environment.

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Add 'requirements.txt' for Python packages

Make it easy to install Python packages with Pip:

    pip install -r requirements.txt

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Add compatibility header to 'fast_client'

'fast_client' 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 'fast_client'

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

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

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Merge pull request #14 from jvirtanen/fixes/darwin

Regain Darwin support (once again)
Merge pull request #15 from jvirtanen/features/virtualenv

Add support for Python virtual environments
Add compatibility header to 'fix_perf'

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

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Merge pull request #16 from jvirtanen/fixes/darwin

Add compatibility header to 'fix_perf'
Add NASDAQ OMX MoldUDP 1.02a

The protocol version is not mentioned in the implementation name because
last change was made in 2006.

Reviewed-by: Ville Aine <ville.aine@iki.fi>
Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Merge pull request #17 from jvirtanen/features/omx-moldudp

Add NASDAQ OMX MoldUDP 1.02a
proto: Rename 'omx_moldudp.h' to 'omx_moldudp_message.h'

Follow the existing naming convention.

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Makefile: Install 'omx_moldudp_message.h'

Signed-off-by: Jussi Virtanen <jussi.k.virtanen@gmail.com>
Merge pull request #18 from jvirtanen/fixes/omx-moldudp

Fix NASDAQ OMX MoldUDP 1.02a support