Adjust version bounds of array and unix for ghc 7.8
Merge pull request #30 from markus1189/build-on-ghc78

Adjust version bounds of array and unix for ghc 7.8
List API now requires specification of item widget height (removes BadListWidgetSizePolicy exception, automatically restricts height of item widgets in rendering process)
Merge branch 'master' of github.com:jtdaugherty/vty-ui
Update demo programs to use new list API
API (List): add scrollToBeginning, scrollToEnd functions
List: now let the list item widget default attribute apply to any padding added to the image
BUGFIX: List: scrolling a list with no elements no longer crashes with V.! error
BUGFIX: use correct constructor to set Shift-Tab as the previous focus keybinding (fixes #31)
API: edit widgets now support limiting line length via set/getEditMaxLength (fixes #33)
Core: mergeFocusGroups now just requires at least one non-empty group
Add explicit collection programming demonstration
collection demo: improve key handler
BUGFIX: TextZipper: ignore more invalid cursor positions (fixes #29)
BUGFIX: h/vFixed: add sufficient padding to prevent empty images from disrupting fixed dimensions (fixes #34)
Docs: correct documentation for boxFixed
Improvement: edit widgets now bring in old content on the left on backspace rather than hiding what is being deleted (fixes #35)
Fix syntax error; sloppy! (fixes #36)
Adds `indexOf` support to the List API
Allows to `select` list elements before the list is rendered for the
first time.  This can happen when you try to select an item in a
list, right after it has been created.