Calysto-scheme

* Moved implementation data structures to datastructures.ss
* removed filenames from info, use index instead
* fixed a bug in StringIO strings
* Optimizations on strings
* Show verbose output when selecting filtered assertions in run-tests
* added new string-join
* Show exception on do_execute_file()
* Add data_files for kernel.json install
* Added ~ home expansion in cd (python)
* assert now raises AssertionError
* Allow test group names to be strings; allow partial matching
* New (host-environment)
* Added (hasitem)
* check for duplicate unit test group
* new (clear-unit-tests)
* New define-syntax via function
* Added (get-completions), (macros); removed macros from dir
* memv should use eqv_q
* Cleanup of exit/quit: tell users to ^D
* Use correct help_obj in jupyter

* Refactor internal defines
* Fixed bug in random(int) in Python host
* Added positive_q to Python host
* Random prim for Python host
* Better eq? for ints and floats
* Better repr for Box
* Changed name to truncate_to_integer
* int() truncates in Python host
* Added box functions to Python host
* Define sort as a prim in Python
* Fixed sort on Scheme host
* Redefined symbol? in Python
* In debugger, print rather than return inspector expr

* Allow named parameters to DLR functions
* A better do_function_direct
* Restore error when args don't match
* Allow use of λ for lambda
* Added expt - raise to a power
* Document latex vars and getitem/setitem

* latex-style unicode variables
* complex numbers are numbers

* setitem fixed
* setitem can set properties

* proper errors
* version number in banner