Refactor function options management

[gmaze]

I noticed that some of the pyowc functions do not use the same options order policy !
For instance:

# Calculate mapped values needed for the analysis
owc.calibration.update_salinity_mapping("", USER_CONFIG, FLOAT_NAME)

while we have:

# Set the calseries parameters for analysis and line fitting
owc.configuration.set_calseries("", FLOAT_NAME, USER_CONFIG)

see how USER_CONFIG comes first and then second ...

when refactoring the code, this must be addressed.

[gmaze]

closing because this is definitely deal with in #29 !