use compiler flag check macro
use sylpheed-plugin-factory as submodule
support Travis-CI
use submodule m4 macro
use submodule common makefile
specify sylpheed build directory
update submodule
use sylplugin_factory_source_dir
remove needless declarations
move declarations to source file
include sylplugin factory header
add gettext related stuff
include config header
fix mixed declarations and codes
update submodule
define SYLPF_ID and SYLPF_OPTION
use DEBUG macros
integrate ui related stuff
fix mixed declarations and codes
remove unused variables