Fix some Markdown formatting issues in the README.
Fix some Markdown formatting issues in the README.

ArCorvus/ue4-hg-plugin,enlight/ue4-hg-plugin,enlight/ue4-hg-plugin,ArCorvus/ue4-hg-plugin,ArCorvus/ue4-hg-plugin,enlight/ue4-hg-plugin