Stop setting WITH_UIP6=1 in example Makefiles

It achieves exactly nothing other than generate confusion
Don't specify -DUIP_CONF_IPV6 in platform makefiles

Makefile.include has done it for us already, we no longer need to do so ourselves
Fix: preserving blank characters (tabulator and space) in Cooja serial output
Merge pull request #428 from g-oikonomou/config-sanity

Remove unnecessary stuff from various Makefiles (Config Sanity, Pt 1)
Merge pull request #469 from eberlin/cooja-tab-char

Fix: preserving blank characters (tabulator and space) in Cooja serial output
Allow configuration of pcap output file
Allow user configuration of RadioLogger pcap file
Merge pull request #475 from cetic/cooja-radiologger-pcap

Allow user configuration of RadioLogger pcap file
Removed the experimental checkpointing code
Enabled shell_rime_send_cmd_init() so that this example can be used in the shell/03-sky-shell-command regression test