Added XP table support in the creatures.cfg file.

Final part and fixes #152 Whoo!
Check better for invalid XP return values.

Based on @hwoarangmy's input on this.
Small stats refreshing fix.

+ small code cleanup while seeing it.
Add a button to grab easily workers in the in game menu
fixes #84

Concerning the worker pickup, the logic is :
1 - Take idle worker
2 - Take fighting/fleeing
3 - Take claimers
4 - Take diggers
5 - Take gold digger/depositers or all the rest
For each, we pickup the highest leveled available

Concerning the fighter pickup, the logic is :
1 - Take fleeing fighters
2 - Take idle fighters
3 - Take busy (working/eating) fighters
4 - Then take fighting fighters or all the rest
For each, we pickup the highest leveled available

As a bonus, I've added support to add creatures in the editor. To use it :
- Press C to change creature type (class will be displayed in the top of the screen)
- Press Y to change the creature's Seat
- Press fighter button to add the creature. It will be in the keeper hand
- Drop the creature where you want
Merge pull request #256 from Bertram25/new_parser

Added XP table support in the creatures.cfg file.
Wrong level format for a creature after it has been changed
Merge pull request #259 from hwoarangmy/development

Add a button to grab easily workers/fighters in the in game menu
Add support to put equipment in a config file
In this patch :
- Changed the damage computation so it is not needed to compute for every entity that can attack
- In the level file, we can only add the weapon name, not its definition
- Weapon is not a GameEntity anymore, just a Creature attribute
- In the level file, creature classes and equipments can be tuned (or even created)
Fixes #138

To test it, I've added in the skirmish 2v2 test map a knight with a tuned LongSword, an adventurer with a level created staff.
I've also set the Kobold base attack to 4 instead of 1 and there is a level specific creature : BigDragon.
Note that there is a BigDragon near the player dungeon and BigDragon can spawn in the top right player portal.
Typo as seen by @akien-mga
Added 1v1 multiplayer test map
+ damages should not be < 0 ^^
Merge pull request #263 from hwoarangmy/development

Add support to put equipment in a config file
Added support to display to a loosing/winning player that he has lost/won
When a player looses his dungeon temples, a chat message is sent to his allies
When the whole team looses, a chat message is sent to them saying they lost
Cleaned an unused function in the render manager
fixes #148
Handle trap destruction in the trap doUpKeep rather than in the tile
Add config manager
+ Defined available seat colors in config manager
+ Read global creature & weapons in the config manager
+ updated damage computation
+ fixed a bug when a player wins where we notify everybody
fixes #150
fixes #235
Added a needed import to compile with linux as seen by @akien-mga
+ typos asked by @Bertram25
Support to make a creature/weapon definition extend another one
fixes #265
See how to test in the issue #265
Merge pull request #266 from hwoarangmy/development

Add config manager + other fixes
Stop rendering the tile under the room/trap ground tile.

Thanks to oln for that, it was obvious but my mind would have make it this time. XD

I also remove the gold on ground when all the gold has been dug.
It is misleading and shouldn't be done until we have a better tile for that.
Removed the useless and empty 'Spells' tab from in-game menu.

Let's readd this one when actual work on spells has started.
Add a button to grab easily workers in the in game menu
fixes #84

Concerning the worker pickup, the logic is :
1 - Take idle worker
2 - Take fighting/fleeing
3 - Take claimers
4 - Take diggers
5 - Take gold digger/depositers or all the rest
For each, we pickup the highest leveled available

Concerning the fighter pickup, the logic is :
1 - Take fleeing fighters
2 - Take idle fighters
3 - Take busy (working/eating) fighters
4 - Then take fighting fighters or all the rest
For each, we pickup the highest leveled available

As a bonus, I've added support to add creatures in the editor. To use it :
- Press C to change creature type (class will be displayed in the top of the screen)
- Press Y to change the creature's Seat
- Press fighter button to add the creature. It will be in the keeper hand
- Drop the creature where you want