Various fixes in mkrpa2.py:

    -- Changed regularisation parameter in interband contribution.
       Paradoxically, using a smaller value of epsilon (1e-3) gives
       poor accuracy. This is probably due to the features in the kernel
       being way too sharp.

    -- Use grid parameters in file names

    -- In testing routine, calculate the total charge

    -- Use dimensionless integration variables in RPA_inter.
       In retrospect, the advantage is not clear. It might help
       if I decide to accelerate this routine, though.

    -- Handling of [0, r[0]] interval in RPA_intra

    -- Overall, much better accuracy was now achieved. However,
       RPA_intra is way too slow, and I have to think of some
       method to accelerate it.
adding new file, odedirac.py
odedirac.py has been edited within the meeting and seems to be correctly measuring
both the dos and the charge density for various beta values.
Merge branch 'master' into wet_polish

Conflicts:
	mkrpa2.py
Merge branch 'master' of https://github.com/avshytov/Coulomb-Impurity into wet_polish

Conflicts:
	odedirac.py
Removed .py~ file: these should not propagate through git