Merge https://github.com/yudhik/brain-invoice

git-svn-id: https://brain-invoice.googlecode.com/svn/trunk@10 e6ef879c-6efb-f92a-4ca0-37fcd3c99b0e
add new implementation, buggy in joining many to many with multiple
primary key

git-svn-id: https://brain-invoice.googlecode.com/svn/trunk@11 e6ef879c-6efb-f92a-4ca0-37fcd3c99b0e
Merge https://github.com/yudhik/brain-invoice