use a sample of page number links for large collections

Large collections will have a large number of page links. The browser slows noticeably when inserting the large page links collection into the DOM.
add focus page number set around current page number
extract maxOptionSize to a pager widget configuration option
remove unused variable max_option_size
Merge pull request #711 from camallen/slow_page_number_links

Pager widget - slow table update when there are a large number of page number links
Pager: Fix JSHint code issues from #711
Core parser updates

Added $node to parser "is" parameter, add image parser to core, moved ipAddress to external file & add MAC address parser to renamed parser-network.js file
Pager: modify & add to widget the code from issue #711
Pager: plugin again updates output display on init
Core: add config & jQuery table object parameters to onRenderHeader function
Demos & themes: include caption in metro theme; add to various demos
Editable: make updatable. Fixes #732
Filter: wildcard filter match behaves logically. Fixes #727
Pager: Add url check to allow ajax updating of table. Fixes #730
Parsers: Update all date parsers to ensure valid dates
p must have ajaxObject, setting it up at init so we can use it to compare later on
Merge branch 'working' of github.com:Mottie/tablesorter into working
Pager: check for dynamically changing ajaxUrl option & cleanup
Filter: add filter_cellFilter option. Fixes #731
Core: fix ARIA caption label reference