Add T-Beg example markov chain

examples/tbeg-dist-paper

+(R^X)^{a,b}
+# actually the functor is: (DX+1)^{a,b}
+# but I want to keep the notation short, and fortunately, DX+1 is a subfunctor
+# of R^X
+#
+# Figure 4 of
+#
+#   Explaining Non-bisimilarity in a Coalgebraic Approach: Games and Distinguishing Formulas
+#   Barbara König , Christina Mika-Michalski, and Lutz Schröder
+#   in CMCS 2020 (D. Petrişan and J. Rot (Eds.): CMCS 2020, LNCS 12094, pp. 133–154, 2020.)
+#
+# The file is also shipped with the TBeg-Utility
+# https://www.uni-due.de/theoinf/research/tools_tbeg.php
+#
+# The present file has been generated from the following python script:
+#
+#   n = 5  # number states
+#   A = "ab"  # list of letters
+#   A_ = len(A)
+#   s = '0.3,0,0,0,0.7,0.8,0,0.2,0,0,0,0,0.3,0,0,0,0,0.2,0.7,0.8,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1'.split(',')
+#   names = [f's{i}' for i in range(1, n+1)]
+#   dist = lambda start, l:  ', '.join([ f'{to}: {w}' for to, w in zip(names, s[start * n * A_ + l:(start+1) * n * A_:A_]) if w != '0' ])
+#   outgoing = lambda start: ', '.join([l + ': {' + dist(start, k) + '}' for k, l in enumerate(A)])
+#   print('\n'.join([names[i] + ': {' + outgoing(i) + '}' for i,_ in enumerate(names)]))
+#
+s1: {a: {s1: 0.3, s3: 0.7}, b: {s3: 0.8, s4: 0.2}}
+s2: {a: {s2: 0.3, s5: 0.7}, b: {s4: 0.2, s5: 0.8}}
+s3: {a: {s3: 1}, b: {}}
+s4: {a: {}, b: {}}
+s5: {a: {s5: 1}, b: {s5: 1}}