Add 'ac_fit' ROOT analysis routine rule
Add exponential auto-correlator fitting routine
Split 'analisi.cpp' into 'analisi.cpp' (auto-correlator) and 'binning.cpp' (binning)
Add rule to compile 'ac_fit'
Add routine to get susceptivity (specific heath) from magnetization (energy)
Exclude first point from fitting domain
Add  to 'distclean'