analysis_online should be rewritten to use cf class

[kostrzewa]

Currently, the analysis of online measurements relies on a number of legacy routines which work, but may produce somewhat inconsistent results. For instance, the PCAC effective mass is computed from the symmetric effective mass definition, while the pion effective mass is computed using invcosh. The return values of the various functions are also highly inconsistent.

This will require rewriting the uwerr functions for these observables, with the benefit that these can then be used elsewhere to check the results of blocked-bootstrap-based fits.