Add support for Amazon Linux

- Install yasm from chef cookbook and not directly from package (as in
Amazon Linux there is no yasm package, it will be compiled from source)
Add cookbook name
Created an LWRP to install ffmpeg modules (codecs).

Can install them from package or from source (default source)
Moved the dependencies install to a separate recipe.

Install the all needed ffmpeg modules depending on the compile_flags.
Added the ability to install them from source in order to add support
for Amazon Linux as they are not available from packages.
Changed the ffmpeg git repo to the new one
Only run the compile_ffmpeg bash resource when the binary file does not exist (or when other resource notifies)

The creates attribute on the bash script does not work as expected, as
the final chef-client run reports that the resource was updated even if
it didn't run. So delete the ffmpeg binary file to trigger the build
process.
The same goes for the ffmpeg_module provider
Notify updated_resource immediately on the ffmpeg_module provider
Specify tested Amazon Linux version on the metadata file
+ git ignore
* use yasm:source for ubuntu
Merge branch 'amazon_support'