bots: Add non-obligatory initialize func for bots.
bots: Add non-obligatory initialize func for bots.

A bot that implements `initialize(client)` has initial
access to the `client` object, before `handle_message`
is called.

jrowan/zulip,dhcrzf/zulip,punchagan/zulip,Galexrt/zulip,brainwane/zulip,jrowan/zulip,mahim97/zulip,amanharitsh123/zulip,showell/zulip,Galexrt/zulip,andersk/zulip,eeshangarg/zulip,showell/zulip,brainwane/zulip,tommyip/zulip,hackerkid/zulip,brainwane/zulip,showell/zulip,rht/zulip,zulip/zulip,punchagan/zulip,mahim97/zulip,vabs22/zulip,brockwhittaker/zulip,shubhamdhama/zulip,shubhamdhama/zulip,amanharitsh123/zulip,vabs22/zulip,rht/zulip,tommyip/zulip,jrowan/zulip,vabs22/zulip,eeshangarg/zulip,jackrzhang/zulip,brockwhittaker/zulip,verma-varsha/zulip,rishig/zulip,jackrzhang/zulip,eeshangarg/zulip,rht/zulip,mahim97/zulip,synicalsyntax/zulip,rishig/zulip,brockwhittaker/zulip,shubhamdhama/zulip,timabbott/zulip,showell/zulip,jackrzhang/zulip,timabbott/zulip,verma-varsha/zulip,dhcrzf/zulip,eeshangarg/zulip,showell/zulip,synicalsyntax/zulip,timabbott/zulip,showell/zulip,jackrzhang/zulip,kou/zulip,vabs22/zulip,kou/zulip,punchagan/zulip,brainwane/zulip,synicalsyntax/zulip,zulip/zulip,vabs22/zulip,vabs22/zulip,andersk/zulip,synicalsyntax/zulip,amanharitsh123/zulip,punchagan/zulip,synicalsyntax/zulip,Galexrt/zulip,kou/zulip,amanharitsh123/zulip,shubhamdhama/zulip,zulip/zulip,hackerkid/zulip,kou/zulip,synicalsyntax/zulip,verma-varsha/zulip,zulip/zulip,mahim97/zulip,eeshangarg/zulip,dhcrzf/zulip,brockwhittaker/zulip,brockwhittaker/zulip,rht/zulip,tommyip/zulip,tommyip/zulip,vaidap/zulip,timabbott/zulip,dhcrzf/zulip,rishig/zulip,eeshangarg/zulip,mahim97/zulip,hackerkid/zulip,andersk/zulip,verma-varsha/zulip,jackrzhang/zulip,dhcrzf/zulip,amanharitsh123/zulip,jrowan/zulip,dhcrzf/zulip,shubhamdhama/zulip,rishig/zulip,hackerkid/zulip,andersk/zulip,rht/zulip,hackerkid/zulip,vaidap/zulip,zulip/zulip,jrowan/zulip,hackerkid/zulip,rishig/zulip,rishig/zulip,jackrzhang/zulip,punchagan/zulip,verma-varsha/zulip,verma-varsha/zulip,zulip/zulip,timabbott/zulip,hackerkid/zulip,timabbott/zulip,vaidap/zulip,rht/zulip,synicalsyntax/zulip,Galexrt/zulip,Galexrt/zulip,punchagan/zulip,shubhamdhama/zulip,kou/zulip,brainwane/zulip,brainwane/zulip,mahim97/zulip,kou/zulip,timabbott/zulip,rishig/zulip,kou/zulip,andersk/zulip,vaidap/zulip,vaidap/zulip,eeshangarg/zulip,jackrzhang/zulip,Galexrt/zulip,brockwhittaker/zulip,showell/zulip,jrowan/zulip,tommyip/zulip,dhcrzf/zulip,shubhamdhama/zulip,brainwane/zulip,tommyip/zulip,rht/zulip,vaidap/zulip,Galexrt/zulip,amanharitsh123/zulip,tommyip/zulip,andersk/zulip,punchagan/zulip,zulip/zulip,andersk/zulip