Remove a deprecated method call and fix a NPE.

Probable fix for #95.
Fix a deprecated Gradle plugin name.
Replace an ellipsis string with a character.
Remove a stray character from a layout file.
Suppress an unnecessary warning.

Suppressed "Image without contentDescription" warning for decorative
image.
Fix namespace on menu attributes.

Replaced numerous instances of "android:showAsAction" with
"app:showAsAction," as required when using the appcompat library.
Update build tools version to 21.0.1.
Revert "Fix namespace on menu attributes."

This reverts commit 861b7bf2154b38491d1737f875b1ed3a9d9e677b. It turns
out that we don't actually need to use the appcompat library, so there's
no need for these changes.
Remove appcompat library.

Our minimum SDK version is 14, so this library is not necessary.
Fix layout_height for a couple of ScrollViews.

Replaced the incorrect "match_parent" attribute value with
"wrap_content."
Suppress a lint message.

We intentionally create a toast without showing it, as explained in a
comment near the newly added annotation.
Disable RTL support in manifest.
Suppress lint message on setJavaScriptEnabled.

We need to enable JavaScript in order to display polytonic Greek
characters.
Simplified a conditional.
Remove a log message.
Remove a couple of unused fields.
Add some assert statements to catch NPEs.
Add some @nonNull annotations.
Remove an empty "if" statement.
Eliminate unused variable assignments.