Merged the battle and common dialogue supervisor back into one.

This permits to trigger a dialogue in any game mode.

- Also made the speaker be string references.
- Used string reference for dialogue id.
-> Both simplifies a lot the scripting of dialogue out of the map mode.
- Added support to load a script in the shop mode.

- Fixed mistakes in the use of compile weight in the c::b file.
- Adapted all the scripts where necessary.

Hardest part of #107

What's left is to actually start scripting a dialogue in the shop mode now,
and test there.
Replaced the en@quot translation rule by en_GB.

It is much more precise about the english type used and fixes #355
Add a first version of a WIP offline manual

This one will be installed optionally along the game, and be used a later reference
for the in-game manual.

Part of #7
Kept a bit on the manual...
Kept on the offline manual a bit...

Part of #7