Added getParameterSetInfo and parameterSetInfo.

getParametersSetInfo returns the information of a specified parameter
set contained in a parameterSetInfo object.
Added getParameterInfo and parameterInfo

Similar to getParameterSetInfo getParameterInfo returns the information
of a parameter in a parameter set. The information is contained in an
object of parameterInfo.

In addition __getitem__ of getParameterSetInfo has been implemented
which returns the parameter info of the specified parameter contained in
a parameterInfo object.
Added getParameter and parameter

Added getParameter which returns the specified parameter of the
specified parameter set as a parameter object. The object contains the
set name, parameter name, data and the human readable units.

getParameter takes a dtype if no dtype is specified the RAW data from
the shotfile should be read. However this does not work. libddww returns
an empty buffer.

Note the datatype 1974 has been added to __dataformat__ returning
numpy.dtype('S8') which is the corresponding data format for CHAR*8.
Unfortunately this could not yet be tested due to the bug mentioned
above.
Added getParameterSet and parameterSet

getParameterSet returns a parameterSet object containing the specified
parameter set. parameterSet is derived from dict and contains the
parameters of the parameter set as elements.
Merge pull request #25 from BSieglin/master

Added parameter functionality