deleted example from ipol.py

added example for adjust.py, deleted example from adjust.py

Implemented compose_weighted and verified its working in examples/compose_by_height_example.py

modifications to AdjustAdd and examples in __main__ (TODO transport to examples)

version to test comp.compose_ko

Adjusted documentation plus a few cosmetic changes

Added functions compose_ko and compose_weighted.
compose_ko works, compose_weighted is still only a stub

atten.py: changed initial k-Z-parameters to c-band specific parameters

added data convention for attenuation input in atten.py

added AdjustBase, AdjustAdd, Raw_at_obs classes plus helper functions in adjust.py

Added examples/compose_by_height_example.py - composition by height in
preparation to more generic composition routines.

Enabled further multidimensionality of the coords argument by summing the
squares over 'the last' dimension instead of 'the second' dimension.

Added missing numpy import

Small docu change

adding information to the module adjust.py docstring

adding one basic interpolation class IpolBase from which all other classes (Nearest, Idw, Linear) inherit

changed the accumulation period suggestion to a more general/flexible time
period than a year

Added four thirds earth radius model.
Adjusted module documentation.

modified module docstring in ipol.py

added an interface to scipy.interpolate.LinearNDInterpolator so that we have a
common interface for all Interpolators (which are Nearest, Idw, Linear)