Allow sloppy dropping of items on to Inventory/Stash/Vendor

Fixes #1060

Other fixes:
- Cached drag icons now have abbreviated quantities like slots do
- Equipment slots are now highlighted regardless of drag source
Merge pull request #1065 from dorkster/fixes

Allow sloppy dropping of items on to Inventory/Stash/Vendor
Parse files one at a time in EnemyGroupManager

Loading enemy files to read enemygroup information was done by
essentially concatenating all of the enemy files together. This broke
the ability to overwrite that data via the same file across mods.

Instead, we now get a list of all the enemy files and parse each one
individually.
Implement more consistent file parsing method

Closes #1040

Now by default, all mod files will overwrite eachother. For files that
were automatically concatenated before, they can still be concatenated
by making the first line of all but the first file "APPEND". For
example, we can combine the credits for the engine, fantasycore, and
alpha_demo by adding "APPEND" to the top of the credits cutscene files
in fantasycore and alpha_demo.
Remove usage of Quest index

Instead of reading quests/index.txt to find out which quests files to
load, we now just grab all the files in quests/. This is consistent with
how we load enemies in EnemyGroupManager, and means one less file for
modders to worry about.
Fix a segfault when dealing with erroneous menu power definitions.

If there was a power with no id attribute, you could crash the engine
by hovering the mouse over this power.

To reproduce the bug apply the following patch to the current flare-game:
--8<--
From 30545c2f1d006eed79641a8a9e54cb5f367f5ac5 Mon Sep 17 00:00:00 2001
From: Stefan Beller <stefanbeller@googlemail.com>
Date: Thu, 17 Apr 2014 18:05:39 +0200
Subject: [PATCH] show engine crash

---
 mods/fantasycore/menus/powers.txt | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/mods/fantasycore/menus/powers.txt b/mods/fantasycore/menus/powers.txt
index 787816b..2db9c04 100644
--- a/mods/fantasycore/menus/powers.txt
+++ b/mods/fantasycore/menus/powers.txt
@@ -15,7 +15,7 @@ label_title=160,8,center,top
 close=294,2
 unspent_points=160,396,center,top
 #unspent_points=hidden
-tabs=3
+tabs=4

 tab_area=32,30,240,348

@@ -28,6 +28,10 @@ tab_tree=images/menus/powers_tree.png
 tab_title=Magician
 tab_tree=images/menus/powers_tree.png

+tab_title=test
+tab_tree=images/menus/powers_tree.png
+
+
 # First tab has index=0
 # Don't add tab_title=, tab_tree=, and tab= keys if you use only 1 tab

@@ -251,4 +255,6 @@ requires_defense=3
 requires_point=true


+[power]
+tab=4

--
1.9.2.655.g72ce72a
Merge pull request #1068 from stefanbeller/master

Fix a segfault when dealing with erroneous menu power definitions.
Update the settings/save file paths in README.engine
Merge pull request #1069 from dorkster/readme_fix

Update the settings/save file paths in README.engine
Use ItemStorage::add() for Stash and Inventory add() functions

Closes #33
Merge pull request #1070 from dorkster/itemstorage

Use ItemStorage::add() for Stash and Inventory add() functions
Build with SDL 2 by default, but still support SDL 1.2

Closes #1064

Changes:
- SDL 2 libraries/headers are searched for in CMakeLists.txt
- getJoystickName() and getKeyName() added to InputState
- Copied over SDL_VERSION_ATLEAST statements from previous SDL 2 work
- Reset FULLSCREEN, HWSURFACE, and DOUBLEBUF when resolution changing
fails in GameStateResolution
- Wrap the appropriate code in SDLRenderDevice with SDL_VERSION_ATLEAST
Add RenderDeviceList for picking render backends at runtime
Move setSDL_RGBA() to private SDLRenderDevice function

This function could be part of the RenderDevice class, but I'm pretty
sure only the SDLRenderDevice makes use of it. Either way, it can't have
it's current scope in RenderDevice.h, as it will cause problems when
compiling with multiple RenderDevices enabled.
CMakeLists: make compatible with clang3.4

clang 3.4 is now standard at the travis building service and clang 3.4
seems to not support -fwhole-program.

Also remove the additional linking to lstdc++ if the compiler is clang.
We're a C++ project, so we'd want to use clang++ instead of clang.

Also removed -fno-enforce-eh-specs, which violates the C++ standard,
but may be useful for reducing code size in production builds.
Merge pull request #1071 from dorkster/sdl2

Allow building with SDL 2 and create RenderDeviceList
Merge remote-tracking branch 'mainline/master'

Conflicts:
	CMakeLists.txt
Merge pull request #1072 from stefanbeller/master

CMakeLists: make compatible with clang3.4; repair travis build
Update Japanese engine translation.
Merge pull request #1073 from Paul-Wortmann/master

Update Japanese engine translation.