Moved most of TextBox speeds into the configuration file

I did not changed the occurrence at:
src/modes/shop/shop_utils.cpp#328

The occurrence at;
src/modes/map/map_treasure.cpp#121
had a value of 50, not 30, but now it's the same than for
other situations (except shop_utils)

It could be interesting to split thos vairous speeds into more
configuration options.

I also have noticed that for battles, there are a lot of identical code.
Merge pull request #303 from bmorel/master

Moved most of TextBox speeds into the configuration file