Change old 'random' loot events into gold drops

All containers that drop gold are reusable (aka don't depend on
a campaign status), and have a 20% chance to drop nothing at all. Some
special containers, such as Maddox's chest and the locked Brothers'
chests have fixed 100% drops of gold. Ideally, we should put some rare
items in those containers instead.
lmb attack now obeys MAIN1 lock
Merge pull request #434 from josephbleau/lockfix

lmb attack now obeys MAIN1 lock
no need to copy an ItemStorage here, this is probably optimized out by gcc/mingw but in MSVC this crashes the program when compiled: as it is the temporary ItemStorage is destructed without having its init() called first
Merge pull request #435 from josephbleau/bugfix

no need to copy an ItemStorage here
Fix crash from holding down MAIN1 while loading a map
Merge pull request #436 from dorkster/bugfixes

Fix crash from holding down MAIN1 while loading a map
Remove INSTALL file.

There is still INSTALL.engine which is updated by flare-engine repo.
Reword README and point to INSTALL file.
Fix Frontier quests being completed before they are taken
Merge pull request #189 from dorkster/fixes2

Fix Frontier quests being completed before they are taken
Merge pull request #187 from dorkster/fixes

Change old 'random' loot events into gold drops
Merge pull request #188 from stefanbeller/master

cleanup Readme
Merge branch 'master' of https://github.com/clintbellanger/flare-engine
Fix Ukkonen quest statuses
Merge pull request #190 from dorkster/fixes

Fix Ukkonen quest statuses
Fix inconsistent naming of Tiled maps

Closes #171
Merge pull request #191 from dorkster/fixes

Fix inconsistent naming of Tiled maps
Don't process --game_data if its value is empty

Closes #418
Merge pull request #437 from dorkster/bugfixes

Don't process --game_data if its value is empty