Corrected node.js version requirement.

package.json was being told that nodebb only required version >=0.8.x of node. Per documentation and communication with developers this should be >=0.10.x
Changing this should help users who accidentally run nodebb on node.js 0.8 to run it on a supported version of 0.10.x or highter.
Merge pull request #1961 from RefinedSoftwareLLC/patch-4

Corrected node.js version requirement.