Merge pull request #7428 from haukepetersen/add_rdcli

Makefile.dep

examples/rdcli/Makefile

examples/rdcli/README.md

examples/rdcli/main.c

makefiles/pseudomodules.inc.mk

sys/Makefile

sys/auto_init/auto_init.c

sys/include/net/rdcli.h

sys/include/net/rdcli_config.h

sys/include/net/rdcli_standalone.h

sys/net/application_layer/rdcli/Makefile

sys/net/application_layer/rdcli/rdcli.c

sys/net/application_layer/rdcli/rdcli_standalone.c

sys/shell/commands/Makefile

sys/shell/commands/sc_rdcli.c

sys/shell/commands/shell_commands.c