ATT protocol defines them as int and just because Bluez5 happens to parse
them from command line doesn't mean all other platforms have to
deal with strings too. This avoids a lot of string to int conversions
and vice versa.

Handles should probably fit into short as well but this needs further
verification. For we play safe.

Change-Id: If75ca539b4b2956b9a65ee2a9ef738b0fe3aa2ee
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>