Fixed bug in definition of double2 and double4 *= which caused precision truncation.
Some fixes to invert_test.cpp
Added check for zero source for solvers
Fixed compiler warning in norm check
Merge branch '0.5.1-devel'
Fixed bug in FloatNOrder::loadGhost (gauge_field_order.h)
Removed all generic functions from cpuColorSpinorField into separate color_spinor_util.cu.  All ordering routines from pack_spinor.h into color_spinor_field_order.h in preparation of merging.