[script] add option for config dir and promote wrong icon size to error

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
[script] add option for sorting find output

The order of output from the find command depends on the type of the
filesystem. Add piping to sort from all find commands to get reliable
output for testing the script itself.

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
Merge pull request #5 from sailfish-sdk/confdir-sort

Confdir sort