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.
removed android-support-v4.jar from apklib
proper activity class check

fixed issue https://github.com/JakeWharton/ActionBarSherlock/issues/529
fixed spacing
fixed imports
Merge branch 'Vandalko-master' into dev
Merge branch 'olekp-master' into dev
Add `final` overrides for native action mode callbacks.
Null check correct variable.
Add known-bugs example for #240.
Correct Jelly Bean false positive for #331.
Point to new CI.
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.