mui-datatables v3.3.0

[patorjk]

Branch for the 3.3.0 release of mui-datatables. It contains the following:

• Added support for custom sort function for columns (columns[colIndex].options.sortCompare). Thanks to @GuyShaanan (Added support for custom sort function for columns #1424)
• Test coverage updates to get coverage above 80% (Test Coverage Updates #1425)
• Third click to reset table sorting (available by setting options.sortThirdClickReset to true). Thanks to @danielbyun (Reset sorting #1430)
• Added sortDescFirst option to allow table to sort in desc order first (Override the sort icon on columns #1411)
• Fix for resizable tables when selectableRows="none" (handle constraint issue when resizableColumns is true and selectableRows set to 'none' #1433)
• Updated searchText README (Possible to hide the search bar, yet use the search functionality?  #1429)
• Fixed issue with Close icon on ViewColumns popover in strict mode (Close Button of Show Columns Tool Is Unclickable #1440)
• Added safeguards and documentation clarifying the rowsSelected option. Thanks to @wdh2100 (Enhancement/rowSelected options #1438)

I will probably do a release for this tonight (July 25).

[coveralls]

Coverage increased (+11.9%) to 84.27% when pulling 8607bc2 on v3_3_0 into 1bd92e6 on master.