Merge pull request #1 from stevenhoneyman/master

A few improvements and fixes
Fix for issue #2 - Wrong behavior if ${pkgname}.files folder exists, but empty
Fix for #3: Only md5sums are currently supported for files, added from ${pkgname}.files folder
Now script uses same checksums as used in original PKGBUILD.
Getting only first *sums line, otherwise there can be issues if we have several of them
Put all variables calles to {} brackets
Put remaining variables calles to {} brackets
Put remaining variables calles to {} brackets