Make `get_avatar_url()` thread-safe

Update return type of `sr_get_curlv()`

Bump version to v0.4.0

Fix wrong format specifiers in `get_avatar_url()`

Remove `entry` member from `struct krdict_context`

Remove dead code

Fix `/info` command showing invalid value for `flags`

Rewrite `krdict` module

Bump version to v0.2.1

Implement `/msg` command