'convert unlimited terms' with 'consider existing links' option bug fixed, Mockpress added to the plugin

git-svn-id: http://plugins.svn.wordpress.org/terms-descriptions/trunk@676235 b8457f37-d9ea-0310-8a92-e5e31aec5664
Version 3.1.4: Undefined index notice for text_before and text_after variables fixed
Merge branch 'master' of github.com:vladimir-s/terms-descriptions
External JS libraries were replaced with WP core ones