Various Features Spike Train Generation (NeuralEnsemble#416)

* bug fixed dealing with units

* fixed same unit error in trial shuffling

* added Bielefeld fim.so and adapted filtering and added window param to fpgrowth

* removed max_occ test

* further unit stuff

* debugging for new fim version

* enabled multithreading in fpgrowth

* less verbose in spade

* added correction factor to rate estimation

* only spiketrain with more than one spikes are corrected

* started rearranging the spike train generation: equilibrium rp. and class structure

* enable option equilibrium /ordinary

* annotations

* Fixed bugs for zero rate

* added test of boundary correction

* PEP8

* revert wrongly merged master

* separate from firing rate correction

* simplified recovered rate test

* finished restructuring in classes

* Added lognormal and inv-gaussian processes

* Updated Tests, added Log-Normal, Inverse Gaussian

* PEP8

* added test for invgauss and lognorm

* PEP8

* updated hardcoded SPADE tests

* update hardcoded UE test

* update hardcoded UE test

* update hard-coded spike train synchrony test

* PEP8

* combined Poisson and PPD into one function

* simplified compound poisson process, single interaction process

* deleted unused hidden functions

* added CV test

* added test for CV and first spike & added more comments

* PEP8

* simplified bib-tex entry

* started working in Robins review

* fix breaked test for Joint-ISI dithering

* continued working on Robins review

* fixed bug - in getting first spike function

* finished working on Robins review, improved first-spike function

* changed to return None for option in init

Co-authored-by: stellalessandra <a.stella@fz-juelich.de>
Co-authored-by: Alessandra Stella <stella@front.cluster>

doc/bib/elephant.bib

@@ -366,7 +366,6 @@ @article{Stoica2005
   title={Spectral analysis of signals},
   author={Stoica, Petre and Moses, Randolph L and others},
   journal={Prentice Hall},
-  pages={},
   year={2005},
   publisher={Pearson Prentice Hall Upper Saddle River, NJ}
 }
@@ -400,3 +399,12 @@ @article{Yu2008_1881
   pages={1881--1888},
   year={2008}
 }
+
+@article{Deger12_443,
+	author = {Deger, Moritz and Helias, Moritz and Boucsein, Clemens and Rotter, Stefan},
+	journal = {Journal of Computational Neuroscience},
+	number = 3,
+	pages = {443--463},
+	title = {Statistical properties of superimposed stationary spike trains},
+	volume = 32,
+	year = 2012}