Added getHtCore spec helper and fixed countRows/Cols
Fixed Core_alterSpec.js to work with native scroll
Added missing fields initialization in scrollNativeVertical
Removed unused method from abstractFilter
_doDraw method decided into smaller functions and moved to WalkontableTableRender class
Setting initial horizontal scrollbar height
Closing editor on scroll
Fixed abstractFilter, cellCoords, columnStrategy, core, rowStrategy specs for Walkontable.