Includes:

• Added toJson and fromJson to Directions models (added toJson and fromJson to Directions models #854)
• Upgraded dependencies (upgdraded dependecies #853)
• Missing space (missing space #846)
• Add voiceLanguage to MapMatchingMatching (Add voiceLanguage to MapMatchingMatching #847)

Release checklist @danesfeder

• If there's a new SNAPSHOT version, then update this repo's README.md file
• Change version name to 3.4.0 in gradle.properties
• Publish 3.4.0 artifact to Maven Central
• Change version name back to 3.5.0-SNAPSHOT
• Update CHANGELOG.md
• Tag v3.4.0 in GitHub
• Update Maps SDK dependency

Post-release @langsmith

• Add the Mapbox Java packages' API reference docs to the their respective folders in /android-docs/api/mapbox-java
• Update the constants.js file in android-docs repo so that compile 'com.mapbox.mapboxsdk:mapbox-sdk-services:x.x.x' line is updated in the Gradle section of the MAS overview page
• Update the Android demo app
• Update version # in config files in /help @langsmith
• Update version # in Studio Preview
• Update version # in cnplgn

/cc: @mapbox/android