python: Add support for python3+

Added a --with-python=VERSION option to configure.ac, and changed the
python destination to work with both python2 and python3. Tested with
python 2.7 and 3.3.

The configure check defaults to searching for the unversioned "python"
package.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
lua: Silence a compiler warning

Define LUA_COMPAT_MODULE in lua-utils.c, to silence a compiler warning.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
.travis.yml: Add python & riemann dependencies

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
basicfuncs+: Fix a think-o

When parsing a number, during any of the numeric template functions, and
the parse fails, display the error message correctly. Previously, the
same error message was displayed for both the first and the second
argument, and both messages said "first argument".

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Merge pull request #38 from algernon/h/num-parse-fixup

basicfuncs+: Fix a think-o
Merge pull request #36 from algernon/f/travis-update

.travis.yml: Add python & riemann dependencies
Merge pull request #35 from algernon/h/lua/openlib

lua: Silence a compiler warning
Merge pull request #34 from algernon/f/mod-python/py3

python: Add support for python3+
.travis.yml: Test with both Python2 and Python3

This adjusts the Travis CI test suite to test with both python2 and
python3, and also enable silent rules for the distcheck, to make
warnings more visible.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Merge pull request #39 from algernon/f/travis/multi-python

.travis.yml: Test with both Python2 and Python3
configure: check for libperl.so, and do not try to build perl module if not present.

Most ancient and modern Unices have perl interpreter installed, but not all of them have
libperl.so installed by default.
Merge pull request #41 from talien/f/perl-configure-fix

configure: check for libperl.so, and do not try to build perl module if ...