Modify the display of histograms: now can use subplots to display several histograms on one page, can no longer display both dev and eval histo at the same time, can control the number of columns in the legend

Add min-far-value option, rename -l (already used) to -Z, change the way linestyles are handled and make use of them optional

Replace a force_eval option so that no evaluation option is needed when evaluation scores are mandatory

Change the way the scores arguments are passed to the compute() function: it now does not rely on dev,eval pairs anymore and can take any number of different files (e.g. train)

Detailed option description, matplolib setting moved to callback functions, add vertical line option to DET

Various small changes after Amir review: add/remove command options, use matplotlib 2.2.2 functionalities, fix doc

move click options to bob.extension, change default axis for ROC and DET to be ISO conform, add command to generate fakes score files, add options to change title and axis labels

Change test -> eval, set different default tablefmt option, add and remove options, modify tests accordingly, and modify base MeasureBase class so that it can handle several dev/eval scores for each system (e.g. licit/spoofing for PAD)

Add FAR value in the printed output ofThreshold. Make sure EPC title is correct (adding split=False)