Update API and library versions

Updated to use API 20. Cannot use API 21 yet as there is an issue with the tests when
using appcompat-v7:21.0.0.
Rename `TextView` ids
Change parameter declaration to obviate cast
Add `LabeledEditText` custom compound view
Change `LabeledEditText` to `FilterOptionView`
Add `OnCheckedChangedListener` to the `CheckBox` in `FilterOptionView`
Use `FilterOptionView` in `FilterCards`
Modify tests to verify that Add Card button is visible in the action bar after deleting cards
Fix bug where CAB didn't entirely disappear.
Modify `testMarkAll()` and `testUnmarkAll()`

Improve `testMarkAll()` to assert that all list items are checked. Clean up
 `testUnmarkAll()` to assert that **all** list items are not checked rather than
 only counting how many **visible** list items are not checked.
Merge branch 'android/butterknife' into bug/cab

Conflicts:
	gradle/android/src/androidTest/java/bbct/android/common/activity/test/BaseballCardListWithDataTest.java
Integrate ButterKnife with code changed for bug fix
Crashlytics: Ignore files that should not be added to version control
Crashlytics: Crashes during development should not be reported
Fix `testOnClickCheckboxStopActionMode()` and `testOnClickDoneButton()`
Merge pull request #320 from codeguru42/android/crashlytics

android/crashlytics
Merge pull request #314 from codeguru42/android/butterknife

Integrate ButterKnife
Merge pull request #318 from codeguru42/bug/cab

Fix display bug when dismissing CAB
Upgrade to Android Studio 0.9.2, gradle 2.1, and gradle plugin 0.14.1
Merge pull request #317 from codeguru42/API-and-dependency-versions

Update API and library versions