Rebalance of to_hit value for all books

[illi-kun]

To-Hit Bonus for all books per doc\GAME_BALANCE.md requirements:

Base:              -2
Grip:              +0
Length:            +0
Striking Surface:  +0
Balance:           +0
----------------------
Total:             -2

So it should be equal to -2 for all books.

[illi-kun]

Additionally, negative bashing values are removed in accordance with this discussion.

[illi-kun]

... and now I'm thinking that the default value of to_hit = 0 mismatches the value used as a start point for balancing (which is -2). This means that many things (but not all of them) which currently have to_hit = 0 should actually have to_hit = -2.