Improve Exception Handling

[rikai]

Currently Showbot will mostly just bail out in the case of exceptions. A good example of this follows:

14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [plugin] schedule: Registering listener for type `connect`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [on handler] Registering handler with pattern `#<Cinch::Pattern:0x00000005307d48 @prefix=nil, @pattern=//, @suffix=nil>`, reacting on `connect`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [plugin] schedule: Registering executor with pattern `#<Cinch::Pattern:0x00000005307500 @prefix=/^!/, @pattern=/next\s*$/i, @suffix=nil>`, reacting on `message`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [on handler] Registering handler with pattern `#<Cinch::Pattern:0x00000005307500 @prefix=/^!/, @pattern=/next\s*$/i, @suffix=nil>`, reacting on `message`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [plugin] schedule: Registering executor with pattern `#<Cinch::Pattern:0x00000005306678 @prefix=/^!/, @pattern=/next\s+(.+)/i, @suffix=nil>`, reacting on `message`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [on handler] Registering handler with pattern `#<Cinch::Pattern:0x00000005306678 @prefix=/^!/, @pattern=/next\s+(.+)/i, @suffix=nil>`, reacting on `message`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [plugin] schedule: Registering executor with pattern `#<Cinch::Pattern:0x000000053059d0 @prefix=/^!/, @pattern=/schedule/i, @suffix=nil>`, reacting on `message`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [on handler] Registering handler with pattern `#<Cinch::Pattern:0x000000053059d0 @prefix=/^!/, @pattern=/schedule/i, @suffix=nil>`, reacting on `message`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [plugin] schedule: Registering timer with interval `600` for method `refresh_calendar`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [on handler] Registering handler with pattern `#<Cinch::Pattern:0x000000053045a8 @prefix=nil, @pattern=//, @suffix=nil>`, reacting on `connect`
14:37:49 irc.1  | [2016/10/15 14:37:49.367] !! [on handler] Registering handler with pattern `#<Cinch::Pattern:0x000000052fff30 @prefix=nil, @pattern=//, @suffix=nil>`, reacting on `disconnect`
14:37:49 irc.1  | /usr/lib/ruby/gems/2.3.0/gems/google-api-client-0.8.7/lib/google/api_client.rb:662:in `block (2 levels) in execute!': Bad Request (Google::APIClient::ClientError)
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/retriable-1.4.1/lib/retriable/retry.rb:27:in `perform'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/retriable-1.4.1/lib/retriable.rb:15:in `retriable'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/google-api-client-0.8.7/lib/google/api_client.rb:645:in `block in execute!'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/retriable-1.4.1/lib/retriable/retry.rb:27:in `perform'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/retriable-1.4.1/lib/retriable.rb:15:in `retriable'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/google-api-client-0.8.7/lib/google/api_client.rb:636:in `execute!'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/google-api-client-0.8.7/lib/google/api_client.rb:368:in `discovery_document'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/google-api-client-0.8.7/lib/google/api_client.rb:413:in `discovered_api'
14:37:49 irc.1  |   from /home/lee/Programming/IRC/Showbot/lib/models/calendar.rb:62:in `new'
14:37:49 irc.1  |   from /home/lee/Programming/IRC/Showbot/lib/cinch/plugins/schedule.rb:43:in `initialize'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinch-2.3.2/lib/cinch/plugin_list.rb:11:in `new'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinch-2.3.2/lib/cinch/plugin_list.rb:11:in `register_plugin'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinch-2.3.2/lib/cinch/plugin_list.rb:16:in `block in register_plugins'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinch-2.3.2/lib/cinch/plugin_list.rb:16:in `each'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinch-2.3.2/lib/cinch/plugin_list.rb:16:in `register_plugins'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinch-2.3.2/lib/cinch/bot.rb:239:in `start'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinchize-0.4.2/lib/cinchize.rb:122:in `block in start'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinchize-0.4.2/lib/cinchize.rb:112:in `loop'
14:37:49 irc.1  |   from /usr/lib/ruby/gems/2.3.0/gems/cinchize-0.4.2/lib/cinchize.rb:112:in `start'
14:37:49 irc.1  |   from showbot_irc.rb:26:in `<main>'
14:37:49 irc.1  | * starting network_test
14:37:50 irc.1  | exited with code 1
14:37:50 system | sending SIGTERM to all processes

In that case, the error message was due to a misconfiguration of the google-api-client settings trickling down to the the calendar plugin, and misconfigurations are where most of

Bailing out is fine, but we need to bail with a more useful error message that explains what the problems are, and in cases where possible, it would be nice rescue and print an easy to spot error message.

Note: This is a general 'exception handling' bug, not restricted to the above example (though that should also be addressed). This bug should be used to point out cases that need to be handled when they arise.