6lowpan: introduce function lowpan_fetch_skb
6lowpan: zero ipv6hdr struct
6lowpan: rework tc and flbl compression.
6lowpan: setting LOWPAN_MAX_HEADER_LENGTH
6lowpan: silent check if NH_C is not set
6lowpan: remove second check if nexthdr is UDP
6lowpan: use set_hc_ptr_data for nexthdr
6lowpan: introduce new nexthdr defines
6lowpan: do a silent check if nexthdr is set
6lowpan: add new hop limit defines and use them

Remove ttl_value array, because 0 is never defined so we returning
a error for a number which doesn't exist in HLIM.
6lowpan: improve debug functions
6lowpan: rework compress and uncompress addr part

rework compress and uncompress address functions.
6lowpan: rename layer addr to _layer names
6lowpan: use IS_SRC and IS_DEST defines

These defines is to identify for which address the uncompress
address function do a uncompress.

There are two options for a source address or destination address.
6lowpan: remove jump over CID bit

Context based compression is currently not supported and we don't
do anything with this CID bit.

This patch removes to jump over the inline byte.
6lowpan: remove not used arrays
6lowpan: add brackets in for loop

Keep in linux codeing style.
6lowpan: split process of iphc0 in own function
6lowpan: split process of iphc1 in own function
6lowpan: avoid context based connections

We currently don't support context based connections so drop
a warning that it isn't supported at the moment.