Hide horizontal overflow in the results table-region

The overflow is now hidden and the table is scrollable in both the
horizontal and vertical directions.
Expand results table when toolbar expands on scroll
Add button for explicitly hiding and showing the filters
Give preference to show/hide filter button clicks

This commit respects the button click over the scroll action. That is,
if the user chooses to hide the filters by clicking the button then the
scroll action has no effect on the filter panel and only
expands/collapses the toolbar. If the user has take no action with the
button then the filter panel will show/hide on scroll as in the previous
commit.
Fix problem with manual hide override and add filter margin-top

When the filter panel is shown by user click on show button while the
toolbar is expanded at the top, a vertical offset(margin-top) is added
to the context panel to keep it inline with the results table.
Pin the context panel to the top when scrolling
Set the top/right offsets based on workflow position

Since Cilantro usually resides within another container, we cannot
simply use fixed top and right offsets. Instead, this commit takes into
account the position of the results workflow and sets the fixed offsets
based off the results workflow initially. Additionally, when the window
resizes, the fixed offsets of the context panel are recalculated.
Remove unnecessary CSS related to fixed offsets
Use relative offsets for context panel in scroll event handler
Restack context panel whenever it is (re)shown
Ensure ContextPanel is visible when updating offsets
Fix getMaxHeight logic to take in account fixed parents

The offsetTop of the element is not accurate when contained within a
fixed element. This traverses up the element's parents and uses the
top position if a fixed parent is found.
Add support for supplying a height for a restack

This will still not exceed the maxHeight which is either explicitly
defined or defaults to a calculation based off the window height.
Pass the preferred height of context panel during restack
Merge pull request #231 from cbmi/issue-226

Add support for wide result tables