Fix #2134 Horizontal scroll bar covers up last row. 

now WHEN_NEEDED really acts like ALWAYS when the scrollbar is shown.
So the viewport is different, and the sudden scrollbar widths and
heights are set and used in calculations for the various widths and
heights
Fix #2221 (cellNav): Add scrollToFocus method
Merge pull request #2376 from PaulL1/2221_scrollToFocus

Fix #2221 (cellNav): Add scrollToFocus method
regression fix for: #2357 scrolling with large amount of columns,columns
disappear after sort 

scrollTop can now be undefined/null then that value should not be used
for calculating if this is a scroll that doesn't have to update
anything.
Issue #2149 - override expandableRowHeaderColDef.displayName
Issue #2382 - Disable resizing of expandable buttons column
Merge pull request #2381 from MattAtBT/2149

Issue #2149 - override expandableRowHeaderColDef.displayName
Merge branch 'master' of https://github.com/angular-ui/ng-grid into 2382

Conflicts:
	src/features/expandable/js/expandable.js
Merge pull request #2383 from MattAtBT/2382

Issue #2382 - Disable resizing of expandable buttons column
fix for #2311 and other issues in grid editors
Merge pull request #2398 from jpuri/mater_input

fix for #2311 and other issues in grid editors
Merge pull request #2351 from jpuri/master

fixes for #2346 #2303
Merge pull request #2379 from Servoy/row_inserts_before_current_fix

regression fix for: #2357 scrolling with large amount of columns,columns disappear after sort
Merge pull request #2361 from Servoy/scrollbar_when_needed_fixes

Fix #2134 Horizontal scroll bar covers up last row.
Fix #1572 (saveState): create saveState feature
Merge pull request #2402 from PaulL1/1572_save_state

Fix #1572 (saveState): create saveState feature
Fix #2286 (sort): fixes and doco for suppress remove sort
Merge pull request #2404 from PaulL1/2286_sorting_doco

Fix #2286 (sort): fixes and doco for suppress remove sort
Fix #2391 (enh exporter): auto-download CSV, removes need for  and some options
Merge pull request #2405 from PaulL1/2391_csv_download

Fix #2391 (enh exporter): auto-download CSV, removes need for  and some ...