Add tune resonances plot (#809)

* black standalone.py

* first call to tune resonance plot, ok

* black on standalone

* restore stand alone from master

* add resonances.py

* removing unused code

* add resonances.py

* cleaning up code

* fixing flake8 and docstrings

* fixing flake8 warnings

* solving flake8

* moving to ValueErrors

* fixing flake8

* always import at.plot

* moving plt.figure towards the end

* restoring __init__.py

* removing variables from kwargs

* moving default linestyle out of function

* black resonances.py

* add check on nth order Farey; swap position of listresonancestoplot

* make farey collection a dictionary

* moving to index starting at 1

* fix bug for order 7 and above

* adapting to period

* removing a1aux, iaux, a2aux

* fixing flake8

* fixing docstring

* more fixing in docstring

* line properties dict keys set to normal and skew

* fix doc string

* fix doc string

* overlaying two plots

* fixing legend; linestyle and axes

* adds options to overlay axes; sets periodicity instead of period

* fix bug in line width for normal lines above order 5

* addtolabels

* fixing DocString

* return also legend handles and labels

* add show option

* improve DocString, window is ignored when axes are given

* improve DocString, set show to False in jupyterlab

* add create_linepalette to __all__

* fix bug in annotation

* fix bug in linestyle as dictionary; create linedict

* improve DocString; usage of the custum dictionary

* changes in handling of user line properties

pyat/at/plot/__init__.py

@@ -6,6 +6,7 @@
     from .generic import *
     from .specific import *
     from .standalone import *
+    from .resonances import *
 except (ImportError, RuntimeError) as exc:
     print(exc)
     print('Plotting is disabled')