Enhancements to updateFilters() (#971):

• Added support for data with integer and character columns (@mikmart #972).
• Fixed an issue with length 1 options causing filters not to update (@mikmart #973).
• Fixed an issue with slider limits sometimes being incorrectly scaled (@mikmart #974).
• Updates to factor and logical filters now match the initial render (@mikmart #975).
• Disabled status is now also affected by updates (@mikmart #977).

New functions doColumnSearch() and doGlobalSearch() let you do server-side searching with filter search strings. These are particularly useful in conjunction with updateFilters() for implementing dynamic limits for filter controls based on currently filtered data (@mikmart #982).

Server-side searching is now faster when multiple filters are active (@mikmart).

Fix a bug that the column filter didn't work for strings like "+" (@stephan-hutter @shrektan #980).