Update build.sh

fix with update lib png to 1.6.6
Merge pull request #16 from KG7x/patch-2

Update build.sh. Thanks @KG7x !
add ubuntu require script and modifiy ffmpeg compile for completly static (ldd...)
Update readme
Merge pull request #17 from aarnaud/master

FFmpeg 2.1 and full static. Thanks @aarnaud !
halt on libpng build error
more halt-on-error fixes
use older version of libpng

this fixes issue #20
Merge pull request #19 from albertz/master

halt on build error and other fixes. Thanks @albertz !
Avoid fetchurl / build.sh name collisions

Rename TARGET_DIR to EXTRACT_DIR in fetch_url
Merge pull request #23 from Silex/master

Avoid fetchurl / build.sh name collisions
add libopus
Update build.sh
ffmpeg 2.1.1
Merge pull request #24 from amnonbb/master

Add libopus
add pkgconfig path to env
Merge pull request #26 from amnonbb/master

add pkgconfig path to env
ffmpeg 2.1.3
Merge pull request #28 from KG7x/patch-4

Update to ffmpeg 2.1.3
Update build.sh

Update to ffmpeg 2.1.4