Fixed sometimes-crash when a monster destroyed a sludge field

When a monster destroyed a sludge field during mon_in_field() it
didn't update the iterator, which made it possible to continue into
undefined memory. It only hanged for me in my test case, but still
unpleasant.
Fixed potential to iterate past end of fields in mon_in_field

This would happen whenever the last one got rid of itself inside
mon_in_field, as it would increment at the end of the loop even if it
had already been the final one but removed itself while inside the
loop.
Fixed same crashes for player as well
Convert a lot of strings to proper format strings

This is done in order to make these strings more
translator-friendly.
Engine size display now respects system’s locale setting
Alters primer recipe tool requirements to no longer be so brutally restrictive.

Thanks to @kyrahabattoir for showing me some very cool videos about
making your own primers.
Makes sauces liquid.

Thanks to @Mshock777 for noticing this in the first place.
found and fixed a typo; rewrote the item's description in the proccess
and another one in the sma description... i must have been blind not to
see it.
Merge branch 'sludge-crash-fix' of https://github.com/rluddy/Cataclysm-DDA into merge
Merge branch 'formatstring' of https://github.com/Wuzzy2/Cataclysm-DDA into merge
Merge branch 'decimal' of https://github.com/Wuzzy2/Cataclysm-DDA into merge
Merge branch 'primer-recipe-tweak' of https://github.com/Rivet-the-Zombie/Cataclysm-DDA into merge
Merge branch 'sauce-states' of https://github.com/Rivet-the-Zombie/Cataclysm-DDA into merge
Merge branch 'typo-fix' of https://github.com/jcd000/Cataclysm-DDA into merge