Fix unit test after 37a3ec51408d5bfaf7ed8c7a081371dca5b0338b "Input profiles can now be used with no input device connected"
Fix dae1a8516914e61074344335a8eba6c42a61bb16 Added page change feature for Enttec Wing

Unit tests crashed after this commit -- when handling page buttons in applyExtraButtons(), the code didn't check
if data for sliders is actually there. The result was crash in tooShortData test.

Since with page flipping parseData() and applyExtraButtons() need the whole packet (with sliders) anyway,
I decided it's enough to check the size at start of the method once.
Rewritten QVERIFY to QCOMPARE so that error message is more informative.
Merge pull request #102 from janosvitok/unit_test_fixes

Unit test fixes