Add basic Word Study Tool feature.

Addresses #68. I'd still like to add a custom typeface and a setting to
disable this feature.
Add custom font in WebView through CSS injection.

Addresses #68.
Remove unused stylesheet.
Add setting to hide View on Perseus option.

Closes #68.
Add a couple of comments.
Fix menu ordering on tablets.
Clear detail fragment on list reset.

Closes #67.
Update readme and manifest for 1.3.0.