new arg parser for 1d

[EdgarGF93]

• New parser arguments: pixel split, algorithm, implementation...
• Correct typos and prints
• Update documentation
• Fix integrate2d benchmark

New attributes for "pyFAI-benchmark" tool (only 1d integration works fine so far)

New arguments for argument parser:

• Pixel splitting argument (-ps, --pixelsplit): no, bbox, pseudo, full, all (default=bbox)
• Algorithm argument: histogram (-algo, --algorithm), CSR, CSC, LUT, all (default=histogram, CSR)
• Implementation argument (-i, --impl): python, cython, opencl, all (default=cython, opencl)
• Function argument (-f, --function): legacy, ng, all (default=all)
• all argument (--all) (boolean): if True, benchmarks every available method (default=False)
• Not processor argument (--no-proc): if used, skips the benchmark using the central processor (useful if you want to benchmark only GPU devices using --gpu)
• Some changes in the figure legends to be consistent with the documentation of AzimuthalIntegrator

[EdgarGF93]

• Tested 2d integration.
• Clearer plot with legends outside of the axes.
• Annotated vertical dashed lines to indicate the specific detector to benchmark
  
  (after typing pyFAI-benchmark -f ng -2d -algo csr --gpu)