tools: NFD startup script

`nfd-start` starts NFD and RIB daemon.
`nfd-stop` stops NFD and RIB daemon.
They are intended for source installation only.
Binary packages should prefer to use system service mechanism if available.

refs #1488

Change-Id: I09f2168619a47fdc0faa78079b7994f30f41ff75
tools: nfdc support add command

refs: #1407

Change-Id: I35d7d33fda57a34a0a4abc890a5a6dcbc60804c8
core: Adding workaround for missing <byteswap.h> on FreeBSD

This commit also fixes a couple of compilation issues with gcc 4.2.1

Change-Id: Iacc5a742b666849694b6ee947482e78340f74336
core: change LoggerFactory to log error on unknown module

refs: #1524

Change-Id: Ic61b361237429992e647ddf194a3c11f2dd2929b
mgmt: Fixing regression introduced by change in the library

After more consistent usage of exceptions (most of the exceptions now
derived from Tlv::Error), `ndn::io::load` would not normally throw an
exception.

Change-Id: Ifd32653e681b94829007db3750e04754e9976fbd
build: == Dependency change ==  NFD now depends on ndn-cxx library

Change-Id: Ia9dd324a536573b5ac4fe1b73d82af772dc84923
Refs: #1536
core: add support for temporary privilege drop and elevation

Added "user" and "group" options to general section of configuration file.
NFD will attempt to set the effective group and user id to these values
after initializing all management modules.

Added privilege helper to drop and temporarily elevate privileges on demand.

Updated README.md with instructions to configure NFD to drop privileges.

Added handler for general confguration file section.

refs: #1370

Change-Id: Id27140ad2dc2ca14751058691511132a35649d58
nfd-status: Define format and implement --xml option

The ether URI format "ether://01:00:5e:00:17:aa" violates
the URI specification, so it has been changed to
ether://[01:00:5e:00:17:aa] in this commit.

refs: #1438

Change-Id: I1218374b75f919a5e1ab158bbab2e217e64aced3
core: Fixing regression in PrivilegeHelper that prevented running as non-root

PrivilegeHelper was properly initialized only when general section was
present.  When section was omitted, s_privilegedUid/s_privilegedGid/s_normalUid/s_normalGid
variables was not properly initialized (set to 0), resulting in
exception during the subsequent PrivilegeHelper::drop call.

Change-Id: Iffd7f05e7e6c86d227da2c9b7920ca6e3b607211