Fix build system to properly support pluggable modules

 * Install *.lua modules into ${DATADIR}/tarantool/1.5
    and *.so modules into ${LIBDIR}/tarantool/1.5
 * Fix default package.path and package.cpath
 * Install Lua headers to ${INCLUDE_DIR}/tarantool/1.5
 * Install config.h to ${INCLUDE_DIR}/tarantool/1.5
 * Add a new package - tarantool-dev (server development headers)
 * Use RPM Macroses in rpm.spec
 * Fix tarball generation for Debian
 * Use GNUInstallDirs.cmake to setup directories
Merge branch 'modules-fix-for-stable' into stable
Merge branch 'stable'

Conflicts:
	debian/tarantool-sql-module.install
	extra/rpm.spec.in
	src/lua/init.cc
	test/CMakeLists.txt
Merge remote-tracking branch 'origin/master'