Rethink about numbering system

[chaoxu]

The numbering system is quite adhoc now.

We will build a somewhat simpler number filter.

So here is the idea:

• there are some counters
• we record the value of ALL counters at each position where the value of the counters matters
• we also set which counters would reset when some other counter operation happens (for example, section increase reset all theorem counter). this need to be defined.

All these information would be passed down.

Actual turn those counter into a presentation would be done by another filter.