HTML export: Make sure that <thead>, <tfoot>, and <tbody> appear in that order, to follow the HTML standard, and also use <th> in the <thead> and <tfoot> sections
EvalMath: Clarify a parameter type in inline docs
ExcelReader: Fix visibility of a class property.
Table Model: Add an event notifier action hook that is run when a table is saved/edited.
Table Model: Use the correct variable as a parameter for extending a WP_Error ($table['id'] would fail as $table is the WP_Error object)
Table Model: Move the "tablepress_event_copied_table" action hook from the add() to the copy() method
Extract formula evaluation and calculation methods from the TablePress_Render class and move them to their own TablePress_Evaluate class
Formula evaluation: Make sure that evaluation results are strings, so that cells remain strings
Adjust the language in the inline commits for some EvalMath unit tests
Add unit tests for the TablePress_Evaluate class