fix final lint errors
The last remaining lint errors are all related to style XML being used in older Android versions.
@pserwylo since you did that XML work, could you take a look? I looked briefly at it and it didn't seem like too much work, but I suck at the Android XML stuff. If it would be a lot of work, then it should probably wait until we do more UI overhaul work.
Here are the errors (https://gitlab.com/fdroid/fdroidclient/builds/1519534):
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:92: Error: android:actionBarStyle requires API level 11 (current min is 8) [NewApi]
<item name="android:actionBarStyle">@style/Widget.AppCompat.ActionBar.Solid</item>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:93: Error: android:actionButtonStyle requires API level 11 (current min is 8) [NewApi]
<item name="android:actionButtonStyle">@style/SwapTheme.Wizard.ActionButton</item>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:115: Error: android:textAlignment requires API level 17 (current min is 8) [NewApi]
<item name="android:textAlignment">center</item>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:120: Error: android:fontFamily requires API level 16 (current min is 8) [NewApi]
<item name="android:fontFamily">sans-serif-light</item>
~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:124: Error: android:textAlignment requires API level 17 (current min is 8) [NewApi]
<item name="android:textAlignment">center</item>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:133: Error: android:textAlignment requires API level 17 (current min is 8) [NewApi]
<item name="android:textAlignment">center</item>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:143: Error: android:textAlignment requires API level 17 (current min is 8) [NewApi]
<item name="android:textAlignment">center</item>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:167: Error: android:fontFamily requires API level 16 (current min is 8) [NewApi]
<item name="android:fontFamily">sans-serif-light</item>
~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/fdroid/fdroidclient/app/src/main/res/values/styles.xml:193: Error: android:fontFamily requires API level 16 (current min is 8) [NewApi]
<item name="android:fontFamily">sans-serif-light</item>