package/nodejs: Add node.js v0.12.5 and set as the default version

The version of the V8 JavaScript engine used by node.js v0.12.5 requires
at least an ARMv6 architecture with VFPv2.  For this reason v0.10.39
remains the default for ARMv5 targets, all other targets now default to
v0.12.5.

Signed-off-by: Martin Bark <martin@barkynet.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>