Added a *= operator for quda matrices
refined eigcg code, this is the first stage of the eigcg mixed precision implementation.
added mixed precision eigcg
improved mixed precision eigcg solver
Added simple gauge tools.

- Plaquette with multi GPU support.
- APE spatial smearing with multi GPU support.

The code uses extended gauge fields for multi GPU and a very simple algorithm to
project matrices to SU3 during the smearing process. Feel free to improve everything.
Merge branch 'quda-0.7' of ssh://github.com/lattice/quda into quda-0.7
Dirac mass parameter is now set with the --mass flag at command line for the invert tests.
Fixed bug in single-GPU clover creation.
Fixed size_t -> int truncation in face_gauge.cpp.
Changed Mobius interface such that b_5 and c_5 now use static arrays and not pointers - required for Fortran interface.
Updated Fortran interface for Mobius and EigCG additions.
Fix to Fortran interface.
Updated invert and dslash tests for mobius parameter b_5 and c_5 which are now static arrays.
Reduced compilation time for extended_color_spinor_utilities.cu.
Fixed bugs in tuneKey generation for mixed-precision blas routines.  Fixed bug in mixed-precision reductions for staggered fermions (reduction length was set wrong).
Added a new parameter QudaInvertParam::max_res_increase, which sets how many consecutive increases in the reliable resisdual are tolerated.
New quda_constants.h file for storing static macro-defined variables in QUDA.  Addded Fortran multi-shift solver interface.
added support for arbitrary number of restarts (in the initCG stage) and support for magma-1.5.x library
Contraction code finally ready!

- Simple contraction kernels and gamma5 multiplication in contract.cu
	+ Includes time-slice contractions, plain volume contractions and contractions with a gamma5 inserted in the middle
	+ The output are the 16 dirac components of the contractions

- Covariant derivative implemented

So far only kernels are included, the interfaces will come in another commit
Merge branch 'quda-0.7' of ssh://github.com/lattice/quda into quda-0.7