RetroDays tileset update (14-10-14)

Updated RetroDays10px and RetroDays20px tilesets.
- Accounts for all new tiles in 0.A experimental as of 13-10-14.
- Some tweaks and fixes to existing tiles.
- Separated ASCII fallback into its own png file for both 10px and 20px.
Rename field::getFieldStart and getFieldEnd to begin/end

To allow range based iteration from C++11.
Remove the dirty member of field as it is not used.

Format field::field and field::~field
Apply astyle to some functions in field.cpp

- field::findField
- field::findFieldc
- field::replaceField
- field::move_cost
Replace field iterations with range based loops

Using auto as type of the iteration variable,
Skipping the fieldCount() check, it's pointless.
Moving the cur variable inside the loop, why was it outside? This is not C, THIS IS C++!
Remove raw pointer from field map.

The entries in the map are already allocated on the heap, their address is unchanged by modifications of the map etc. no need for pointers here.

This also fixes a memory leak. The pointers were not freed when the submap was deleted.

Again moving declaration of field_entry* cur inside the loop.
Replace usage of map::field_at with direct map function

Instead of getting the field, than adjusting/querying that field manually, let the map doe all that.
Make spread_gas helper function a map member function
Make create_hot_air a map member function
Make map::field_at return a const reference.

Code outside the map is not supposed to change the fields directly, instead one should use the field related functions of the map class.

Add a non-const get_field function for non-const access the fields.
That function is protected, so it's only usable from inside the class.

Added wrapper for for const access to the field class: iterator begin/end and findField.
Documentation for field related functions.

Remove declaration of field_entry::getFieldMoveCost - it's not implemented, but field_entry::move_cost is implemented.

Simplified map::add_field by using the result of field::add_field to determine whether the field has been added or already existed.
Extract the disabling of robots into separate function

Called before any movement is done.

Also generalizes the logic to get ammo from the turrets back.
Check for displacing immobile monster before actual moving.
Make item type of that monster can be disabled into a json property

Remove the hard coded relation of mon_turret <==> bot_turret etc.

Change the manhack menu because the menu item "Deactivate" is now queried in the common (to all monsters) code above.
The manhack menu only contains the reprogram entry.
Make EMP deactivating a monster consistent with disabling a robot by the player

- using mtype::revert_to_itype for resulting item.
- check for mtype::revert_to_itype to decide whether the monster can be deactivated.
- common code for manhacks and turrets.
- loop through all the ammo of the monster.
Rebalances ketchup

Previously, ketchup had nutritional stats appropriate for 1 serving per
1 volume, giving it 100 nutrition and 200 quench, and a weight of 5
pounds per per plastic bottle.

This tweak divides price, weight, and nutrition by 5 because there are 5
charges per 1 volume. It also nerfs quench because ketchup should not be
more satisfying than soda.
Add correlation between monster HP and monster item damage:

When disabling a damaged turret, the resulting inactive turret item will be damaged according to the relative HP of the turret.
Similar when placing an inactive turret, the created monster will have less than its full HP if the item had been damaged.
Merge branch 'fix-fields-memory-leak' of https://github.com/BevapDin/Cataclysm-DDA into merge
Remove the obscure massage from manhack interaction
Merge branch 'balance-ketchup' of https://github.com/Skidborg/Cataclysm-DDA into merge