Add ability to specify which area is scrollable, rather than assuming it's the window
For scrollable-div, corrects header width on window resize.  Reset header column width to original inline style values when header is no longer sticky.
Wrap toggleHeaders in a condition so no JS errors occur right after destruction; Add leftOffset property, similar to fixedOffset, but can be used for tweaking horizontal alignment
fixed chrome bug: when scrolling past the table and back up again the header would not re-appear.
snake_case to camelCase
bump version