Add Statistics in bear aspects

[shreyans800755]

As per discussion on thread coala/coala-bears#1691 (comment),
and comment by @sils
Add Statistics in bear aspects CAN_DETECT.

[jayvdb]

Personally, I think this is a mis-use of CAN_DETECT. But @userzimmermann is responsible for the design in this area.

Note that @sils and I had a chat the design problems that CLOCBear causes at https://gitter.im/coala/coala?at=591185e0c89bb14b5ae5299a

[shreyans800755]

@jayvdb @sils I've pointed it out in comment coala/coala-bears#1691 (comment).
Either we have to add statistics related logic as suggested by @sils, or we can add CAN_COMPUTE or something like that, and than use it later when other design that uses statistics is ready.

[sils]

IMO either use CAN_DETECT or also an option would be to not list this "aspect" at all. The CAN_DETECTs will be replaced by aspects at some time anyway and the aspects should contain statistics as well, we'll need them.

[shreyans800755]

Then, I think PR for this issue should be good to merge along with coala/coala-bears#1691 for CLOCBear.