Moving files to convenient locations

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Removing "public_header_files" from Liquid.podspec

because it is not being used.

Thanks @RuiAAPeres for your suggestion!

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Merge branch 'development'