NPC: add requires_level and requires_not_level events.
Map Events can have requires_level and requires_not_level.
Merge pull request #312 from stefanbeller/master

Add requires_level and requires_not_level to NPC and Map.
Introduce a setting 'audio' in the config file to disable audio.

Currently this setting cannot yet be set in the userinterface config.
Having this option available, allows us to not call Mix_OpenAudio
if audio is completely disabled, so the audio subsystem is not initialized
at all.
Merge remote-tracking branch 'mainline/master'
Capsule the audio processing better into their own functions.
Fix MessageEngine always being initialized as English

Closes #314

loadSettings() needs to be run after the ModManager is created, but *before*
MessageEngine is created.
Shrink scope of variables.
remove unneeded assignments.
PowerManager: complete init list.
Add Gallaecio to mailmap file.
README.engine: move installation related text into seperate INSTALL.engine file.
Update of swedish translation.
Merge pull request #313 from stefanbeller/master

Introduce a setting 'audio' in the config file to disable audio. 
Merge pull request #315 from dorkster/bugfixes

Fix MessageEngine always being initialized as English
Merge pull request #317 from hean01/translation

Update of swedish translation.
Merge pull request #316 from matthiaskrgr/master

    README: move installation related text into seperate INSTALL file.
Merge branch 'master' of https://github.com/clintbellanger/flare-engine

Conflicts:
	.mailmap