0.2.1

[halilkhrmn]

This PR prepares release v0.2.1. It ships the provider-lookup change from #22 that the F-Droid review asked for, plus the fixes merged since 0.2.0.

• versionCode 3, versionName 0.2.1.
• changelogs/3.txt in en-US, tr, ru, fa and ar, each at most 500 bytes (327–459). They cover:
  • the provider lookup switch;
  • the typed-domain fix;
  • sites typed by hand can be tested without choosing a pack;
  • the new shared site packs.
• The About screen in the store images shows 0.2.1.