message: process only otr related messages
diff: -import { PluginState } from '../../plugin/AbstractPlugin'
  +import { PluginState, EncryptionState } from '../../plugin/AbstractPlugin'
  import PluginAPI from '../../plugin/PluginAPI'
  import { EncryptionPlugin } from '../../plugin/EncryptionPlugin'
  import Client from '../../Client'
  @@ -68,6 +68,11 @@ export default class OTRPlugin extends EncryptionPlugin {
  }
  private afterReceiveMessageProcessor = (contact: Contact, message: Message) => {
  + let plaintextMessage = message.getPlaintextMessage();
  + if (!plaintextMessage || !/^\?OTR/.test(plaintextMessage)) { //@TODO search for whitespace
  + return Promise.resolve([contact, message]);
  + }
  +
  return this.getSession(contact).then((session: Session) => {
  return session.processMessage(message, 'decryptMessage');
  }).then((message) => {
  @@ -76,6 +81,10 @@ export default class OTRPlugin extends EncryptionPlugin {
  }
  private preSendMessageProcessor = (contact: Contact, message: Message) => {
  + if (contact.getEncryptionState() === EncryptionState.Plaintext) {
  + return Promise.resolve([contact, message]);
  + }
  +
  return this.getSession(contact).then((session: Session) => {
  if (session.isEnded()) {
  //@TODO block this message
  