Modifications in Newton-Cotes Integrators

[syedalimohsinbukhari]

[devel-newton-cotes-major-1]

1. minor modification to .pylintrc
2. minor modifications to __init__.py files
3. added __all__ to runge_kutta.py
4. minor modification in polynomial.py
5. Renaming
   1. NewtonCotesIntegrators.py to newton_cotes_integrators.py
   2. NEWTON_COTES.py to newton_cotes.py
6. newton_cotes.py
   1. Added module level doc-strings.
   2. Added class/function level doc-strings.
   3. Reduced multiple self calls to variable calls
   4. Added auto-rounding for data table display but the calculation is performed on un-rounded values.
   5. added solver_helper method
7. newton_cotes_integrators.py
   1. added doc-strings to all NC-integrators.
   2. minor modifications.