add main
make extractd compiled under github/..
make github.com/heartszhang/gextract/... compiled

- rename opml.go's package name to opml
Revert "support atom and rss"

This reverts commit 4ba71f3900860f5f7ed6c0ec2613cc3706735a3f.
move project to github.com/heartszhang
add entry_crawler
Feed add field 'disabled'
remove implicit import meta in file feed_parser.go
add feed-operator remove and disable
remove failed feeds automatically
Merge branch 'master' of github.com:heartszhang/gextract
db_feed add save2 funcs
support search via google-feed-api
Update entry_fetcher.go
add google feed api support