* Add initial support for getting ChannelMember info of all bridges.
Adds an EventGetChannelMembers event, which gets send every x time to
all bridges. Bridges should respond on this event with a Message
containing ChannelMembers in the EventGetChannelMembers key in the
Extra field.
handleEventGetChannelMembers will handle this Message and sets the
contained ChannelMembers to the Bridge struct.
* Add ChannelMembers support to the slack bridge
* Decrease complexity of handleMessage, handleReceive, handleFiles
* Move handlers to handlers.go
* Split ignoreMessage up in ignoreTextEmpty, ignoreNicks and IgnoreTexts
* Add ignoreEvent
* Add testcase for ignoreTextEmpty, ignoreNicks, ignoreTexts and ignoreEvent