Added an eigenvalue solver to implement power method

Iterative method, repeatedly applying the RHS function to
a solution. The result is the largest eigenvalue and
corresponding eigenvector.
pyGridGen: removed dependency on ode.lsode and netcdf4

o Now uses ode.lsode if it's available, but falls back on
  scipy.integrate.odeint otherwise

o Uses boututils.DataFile to write NetCDF files. This
  can use netCDF4, Scientific, or scipy libraries.
pyGridGen: Some fixes and optimisations

o Fixed bug in use of closest_line to find starting
  line for gridding. opt_ri and opt_zi were used (indices)
  rather than the (r,z) coordinates

o Optimised local_gradient a little, creating spline
  objects once rather than every evaluation
Generate grid for O-T
LTOH folder

copy of elm-pb
Update import_data_netcdf.m

Recently I found that different versions of netcdf libraries save data in different format. 
This now can automatically detected by present version of code.
Update import_data_netcdf.m

One more line added which was missed in previous change.
This let MATLAB know the format of netcdf version.
Merge branch 'master' of https://github.com/boutproject/BOUT-dev
control
control
control
Merge branch 'pygridgen'

Conflicts:
	examples/non-local_1d/analyse_slicer
Merge branch 'master' of https://github.com/brey/BOUT-dev

Conflicts:
	examples/non-local_1d/analyse_slicer
Adding missing include to gyro-gem example.
Added RK3 SSP method

Solver:type rk3ssp

3rd order explicit RK scheme, Strong Stability Preserving

www.cscamm.umd.edu/tadmor/pub/linear-stability/Gottlieb-Shu-Tadmor.SIREV-01.pdf

Spatial TVD schemes can become oscillatory if discretised
in time with a non-SSP scheme. These schemes aim to retain
the stability properties of the Euler method, but with higher
accuracy.
Merge branch 'pygridgen'
Adding RK3-SSP solver
Added example of using DataFormat
Merging improvements to Matlab import_data_netcdf

By Sanat Tiwari, IPR, India
Adding instructions for installation on Archer

Small paragraph in the user manual, and give module
load instructions for setting up the environment