Support LinkButton

Merge pull request #4 from katellaco/fix_button

We can now use LinkButton

Fix grey button

v1.5.1.6

remove _default style which caused buttons to go grey

Tweak Action class def

v1.5.1.5

tweak Action class def

Support ephemeral messages

Merge pull request #3 from vusters/ephemeral

Ephemeral

Support unfurling content (which requires passing in user's access token instead of bottoken)

Merge pull request #2 from vusters/link_shared

Link shared

Thread can now broadcast back to the parent channel

Merge pull request #1 from vusters/thread_merge

Enable to broadcast the thread message back to the parent thread

correctly add timezone to Profile

v1.5.1.1

timezone is on User object, not Profile

add Profile timezone

v1.5.1

Add profile timezone