Completed changed the file structure

Transitioned to a folder based approach to group similar files together.
This may or may not reduce complexity but it will be interesting to find out.
Major Refactor:

1. Moved hydro data towards the new generic data store located locally.
2. Created a master csv_loading function. This function has "sane" defaults
   and takes a series of key word arguments in order to define how it should
   process the data it is passed.

   This function makes redundent the range of csv loading files which had a large
   quantity of duplicated code and these have been subsequently removed.

3. Shifted the NIWA date parsing function to the utilities file from the hydrology
   file
Another refactor:

Made some modifications to utilities, specifically a range of prebuilt aggregations
for working with grouping time series and then applying custom, frequently used
aggregations to them.

Not sure if I'll keep all of these.
Added a helper function to merge series and DataFrames together easier
Introduced a few helper functions to make the importation of data for analysis easier

In particular, a new function, "Load master set" will load all of the data
as well as time merging these to promote faster analysis down the track.
This should reduce the amount of redundent time spent merging the same datasets
over and over again
Removed function which has now been superseeded
Made some of the constraint characterisation equations much more general.

Moved the CDF and conditional probability functions across to the utilities
module included with the NZEM module