fix plugin shared object path
use compiler flag check macro
add travis support
use setup-travis.sh script
use submodule m4 macro
use submodule common makefile
specify sylpheed build directory
add git submodule
remove needless definitions
fix mixed declarations and codes
add missing const qualifier
include account header
fix pointer qualifier
use VERSION
Add NULL check for GError
Indent
Add --enable-debug option
Fix a bug that filter rule is wrongly applied

This bug is caused by the way of wrong string comparison.

Reported by case. Thanks!!!
Remove needless empty menu item
Add 0.7.6 entry