rename: interfaces.gr1c.load_aut_xml -> aut_xml2mealy

because it does not load from a file, but converts a string or xml tree to a MealyMachine instance,
until it is renamed to xml2strategy or something analogous.
new func: load_mealy
Merge branch 'master' into strategy
replace \\n -> \n for pydot export

because it makes no difference in the end result.
More detail:

- \n becomes an actual LF in the dot file, but because it is within the label attribute, it is preserved verbatim inside the produced pdf, svg

- \\n becomes the escape sequence \n within the dot file's text. After dot runs, the result is the same.

Note that the same is not expected to hold when using dot2tex, when invoking math mode.
add tikz arg and propagate it
enclose in $…$ only for latex export via SVG, not for dot2tex

because math mode will be used for labels with dot2tex
use graph var directly available, mv comment
replace _decide_node_shape with _is_accepting

so that it can be used by both dot, pdf, svg and tikz export
new: tikz export for use with dot2texi
minor tikz style changes

- no text on initial node arrow
- darker rims, when not already containing black
add newline between node name and label only when label present
add commented dot graph properties

would be useful to expose setting these when calling graph2dot functions
use dict instead of list for label definitions given to LabeledDiGraph.__init__
mv unimplemented load_spin2fts function
add new GameGraph class to transys
rename method FTS.project -> FTS.projection

in accord with method names of builtin classes like set
expose TypedDict in transys subpackage __init__
add example to TypedDict docstring
add option to set default values for typed keys of LabeledDiGraph

by passing a dict of default key-value pairs.
This dict is used to initialized each TypedDict annotating a node or edge.
bugfix: copy default values of labeled graph annotations

to avoid making labels of different nodes (or edges) point to the same object in memory (e.g., set()) when initializing them to the default values.
If that happened, then any direct change, for example adding a new proposition to some label: ts.states[state]['ap'].add('p'), would affect the labels of all other nodes (or edges) as well.