This is a release of some features and fixes that were written after the last 1.7.10 release (6.0), but before 1.8. Notable changes include Forge Multipart support and tree types for /tree, /forestgen, etc.
This version was built on Forge 10.13.4.1614-1.7.10. If you are using an older, incompatible build, you can still find the original WorldEdit 6.0 for 1.7.10 release here.
Quick tutorial: Once you download and install WorldEdit, enter a creative world and type
//wand. Left click one block, right click a different one, and then type
//set glass. You can learn more on the WorldEdit wiki.