* various "style" improvements suggested by PyCharm
* added a few required libs to setup.py
More style/robustness/spelling fixes courtesy of PyCharm warnings
fixed upgrade script by removing the special case for grpmin|max(expr1, expr2) -> min|max(expr1, filter=expr2) as it is in fact not needed and caused problems in some cases
added a function to utils which finds the first occurrence of a character in a string expression at a specific depth in the expression (stack of parentheses/brackets). This is not used currently but might be useful in the future. I developed it to fix the upgrade script before I realized the whole thing could be removed instead.
* use add_context for SyntaxError because some do not contain the faulty string  (eg non-keyword arg after keyword arg).
* catch exceptions in the ast.parse phase of our parse() function because some Syntax errors can be raised at that point.
more "style" improvements suggested by PyCharm
update TODO
update version
added "view" command to open vitables
added experimental chart functions
* added boxplot, plot, stackplot
* cleaned up/refactored the charting code quite a bit
* implemented DelayedImportModule to make it easier to have optional dependencies
* added "axes" property on LabeledArray
* implemented "aslabeledarray" function
fixed plot() and stackplot() x axes which were off by 1