Make links and #streams clickable in messages.
Make links and #streams clickable in messages.

Fix:#638

saketkumar95/zulip-mobile,kunall17/zulip-mobile,saketkumar95/zulip-mobile,nashvail/zulip-mobile,nashvail/zulip-mobile,saketkumar95/zulip-mobile,Sam1301/zulip-mobile,Sam1301/zulip-mobile,Sam1301/zulip-mobile,kunall17/zulip-mobile,saketkumar95/zulip-mobile,Sam1301/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,nashvail/zulip-mobile,Sam1301/zulip-mobile,nashvail/zulip-mobile,saketkumar95/zulip-mobile,Sam1301/zulip-mobile,vishwesh3/zulip-mobile,kunall17/zulip-mobile,kunall17/zulip-mobile,vishwesh3/zulip-mobile