- use qiniu/iconv to replace djimenez/iconv-go
- set powershell console's encoding to utf8
- export FeedSource Subscribe api
- autodetect rss and atom format
- merge FeedsProfile and BackendConfig
- fix struct annotation error
- add dueat fiedl of feedentry and feedsource
- implement dbapi
- make opml test passed

Signed-off-by: hearts <hearts.zhang@gmail.com>
- remove obsolete file opml.go.back

Signed-off-by: hearts <hearts.zhang@gmail.com>
- implement curl

Signed-off-by: hearts <hearts.zhang@gmail.com>
- add some samples

Signed-off-by: hearts <hearts.zhang@gmail.com>