v1.x-1.3.4

Maintenance and bugfix release:

• Issue #119: Do not insert an empty img tag via image dialog by @indigoxela in #120
• Issue #121: Update TinyMCE to v7.2.1 by @indigoxela in #122
• Issue #123: Fix various problems related to figcaption by @indigoxela in #124
• Issue #125: Selecting a linked image should activate both buttons by @indigoxela in #126
• Issue #127: Firefox: floated images wrapped in links by @indigoxela in #128

Full Changelog: 1.x-1.3.3...1.x-1.3.4