Fixed option header bug for large deltas.
Limited observe clock to 24 bits.
Updated buffer definition macro due to core changes.
Updated copyright information.
Updated Erbium (Er) examples and removed unsupported static routing module.
Fixed RPL configuration according to core changes.
Added CoAP ping support.
Fixed stimer issues due to core changes for older Erbium versions.
Fixed broken/unclear Ipv6 configuration with CFLAG.
Merge pull request #276 from mkovatsc/er-coap-13

Erbium (Er) fixes and updates
Merge remote-tracking branch 'upstream/master'