py-asteval: updated to 0.9.31

0.9.31
cleanup numpy imports to avoid deprecated functions, add financial functions from numpy_financial module, if installed.
prefer 'user_symbols' when initializing Interpreter, but still support 'usersyms' argument. Will deprecate and remove eventually.
add support of optional (off-by default) "nested symbol table", based on a Group object that can be accessed from Python either with dict syntax (ie aeval.symtable['x']) or with object attribute access (aeval.symtable.x). In addition, symbols can be found by looking first in the top-level symbol table and then in sub-Groups named in symtable._searchgroups, allowing for a more hierarchical, nested symbol table. This should be considered experimental and is off by default. The make_symbol_table() function gains a nested=False argument to control whether to use this option.
update tests to run most tests with symbol tables of dict and nested group type.
general code and testing cleanup.

0.9.30
add config argument to Interpreter to more fully control which nodes are supported
add support for import and importfrom -- off by default
add support for with blocks
add support for f-strings
add support of set and dict comprehension
fix bug with 'int**int' not returning a float.


(adam)