Check if childIndex is zero being getting previous child

On Gingerbread and possibly older versions of Android
ViewGroup.getChildAt would catch an exception when a
invalid index was requested.

Adding a guard at this layer prevents many exceptions
from being allocated and thrown away at the ViewGroup
layer.
Add SearchView widget which supports a very large subset of the API.

`SearchableInfo` support is currently removed.
Allow empty action views to avoid the wrapper.
Automatically correct ColorDrawable usage on stacked background.

Refs #379. Closes #545.
Ensure ColorDrawable fix is only used on pre-HC.
Merge branch 'dev-fork' of git://github.com/kevinsawicki/ActionBarSherlock into kevinsawicki-dev-fork
Style tweak.
Mention code style guidelines on the website. Closes #542.
Update usage page to latest version and use AJAX to stay up to date.

Closes #544.
Ignore unregister failures on ShareActionProvider. Closes #557.
Next version will be 4.2.0.
Ensure XML onClick definitions perform lookup on correct object. Closes #533.
Call action mode start/finished activity callbacks with the native bar. Closes #491.
Spelling.
Update change log for new things.
Only wrap menu item views which implement our CollapsibleActionView.
Wrap the other unregister call in case we are not registered. Refs #557.
Ensure action view wrapper is not returned.
Fix typo on homepage.
Merge branch 'orrc-patch-1' into dev