Asteval

Fixes:

- fixes for multiple list comprehensions (addressing 126)
- add testing with optionally installed numpy_financial to CI
- test existence of all numpy imports to better safeguard against missing functions (for safer numpy 2 transition)
- update rendered doc to include PDF and zipped HTML

* add deprecations message for numpy functions to be removed in numpy 2.0 (122)
* comparison operations use try/except for short-circuiting instead of checking for numpy arrays (addressing 123)
* add Python 3.12 to testing
* move repository from "newville" to "lmfit" organization
* update doc theme, GitHub locations pointed to by docs, other doc tweaks.

* 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.

* 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.

bug fixes

- add support for Python 3.11
- add support for multiple list comprehensions
- improve performance of making the initial symbol table, and Interpreter creation, including better checking for `index_tricks` attributes