Add preference assertions.

Closes #14.
Merge pull request #16 from square/jw/preferences

Add preference assertions.
Add cursor column assertion.
Remove mutating from cursor column assertion.
Merge pull request #17 from ming13/cursor-has-column-assertion

Add cursor column assertion
Change custom String joiner to use framework one.
Remove utils class.
Merge pull request #18 from ming13/android-textutils

Change custom String joiner to use framework one
Add multi-name column check.
LinearLayout extends ViewGroup.
AdapterView extends from ViewGroup.
Support using string resource ID for most text assertions.
Merge pull request #19 from square/jw/text-by-resources

Support using string resource ID for most text assertions.
Assertions for contains, starts with, and ends with for `TextView` text.
Merge pull request #20 from square/jw/advanced-text-assertions

Assertions for contains, starts with, and ends with for `TextView` text.
TextView is/not empty assertions.
Merge pull request #21 from square/jw/advanced-text-assertions

TextView is/not empty assertions.
ViewAssert#hasVisibility(int). Fix spelling of View#isNotInvisible.
Merge pull request #22 from square/jw/visibility

ViewAssert#hasVisibility(int). Fix spelling of View#isNotInvisible.
Period.