buildsystem: quoted cmake variables

fixes #4, all variables are now enclosed with double quotes: "${var}"
buildsystem: fixed returning false if list doesn't contain requested item
audio: fixed in memory sound loader
audio: game_main now loads in-memory instead of dynamic sounds
Merge branch 'fix_audio'
buildsystem: added sfttech/opusfile ppa to .travis.yml
Merge pull request #99 from mic-e/travisopt

buildsystem: added sfttech/opusfile ppa to .travis.yml
engine: fixed typo in checking max_texture_units
Merge pull request #92 from TheJJ/cmakequotes

quotes for cmake variables
add -Wno-mismatched-tags flag for llvm builds
Argument '--version'
For writing current version of the Openage
Add myself into authors list
Merge pull request #100 from zuntrax/master

add -Wno-mismatched-tags flag for llvm builds
remove redundancy in buildsystem/cpp.cmake
Merge remote-tracking branch 'zuntrax/master'
Merge branch 'VersionLog' of BugExplorer/openage into master
args: fixed whitespace issues
misc: assign the best sounds available for creation and dying
Add a sound_id_destruction to TerrainObject and play it on building destruction
Args.cpp - small typo fix in print section