Issue #154: "FilterCards" activity and layout

Added basic activity and created it's layout.
Issue #154: disabled inputs and layout improvements

All input fields are disabled by default and become enabled when the
corresponding checkbox is checked. Additional layout changes so that
everything looks good.
Issue #154: remove state saving for "Ok" button

No need to save the state of the button as the state of checkboxes is
preserved by default - we can count the number of checked boxes to
restore state of the "Ok" button.
Issue #154: add tests for "FilterCards" activity

Added all the test for "FilterCards" activity, some minor changes and
fixes.
Issue #154: implemented queryBuilder

Removed old filter activities, implemented queryBuilder, updated
"BaseballCardList" to use the new filter, updated "FilterCards" to
return a result.
Issue #154: rewrote existing tests

Updated existing tests to reflect changes to the filter activity.