Add recipe to create /etc/reach-version with build info

This recipe creates and installs /etc/reach-version with
build information in the following form:

root@g2c1:~# cat /etc/reach-version
poky 1.3.1
BB_VERSION        = 1.16.0
TARGET_ARCH       = arm
TARGET_OS         = linux-gnueabi
MACHINE           = g2c1
TUNE_FEATURES     = armv5 dsp thumb arm926ejs
TARGET_FPU        = soft
meta
meta-yocto
meta-yocto-bsp    = danny:2806646a263527ec0487ea160afd4bdc0a3c1703
meta-reach        = master:5095abe0b3dac7a28a4dbe02b1dbd7004037afb7
meta-fsl-arm      = danny:a0e486a76af5819ee76ac34e966feb72bd3c48bd

Signed-off-by: Steve Sakoman <steve@sakoman.com>