initial flex import scripts

Only implements the extratags style for the moment. Tests pass
for the same behaviour as the gazetteer output. Updates still need
to be done.

CMakeLists.txt

@@ -63,7 +63,6 @@ if (BUILD_IMPORTER AND BUILD_OSM2PGSQL)
     endif()
     set(BUILD_TESTS_SAVED "${BUILD_TESTS}")
     set(BUILD_TESTS off)
-    set(WITH_LUA off CACHE BOOL "")
     add_subdirectory(osm2pgsql)
     set(BUILD_TESTS ${BUILD_TESTS_SAVED})
 endif()