FSAdapter typo

[hgardneriv]

Downloaded the npm "_id": "sbtree@3.1.0", tried to use FS Adapter and noticed an issue in:

sbtree/src/types/SBFTree/methods/createRoot.js

Line 8:

if (roo) {
Run Time Error:

(node:28043) UnhandledPromiseRejectionWarning: ReferenceError: roo is not defined
at SBFTree.createRoot (/Users/harrygardner/Documents/code/nodejs/bppTree/node_modules/SBTree/src/types/SBFTree/methods/createRoot.js:8:3)
at SBFTree.insert (/Users/harrygardner/Documents/code/nodejs/bppTree/node_modules/SBTree/src/types/SBFTree/methods/insert.js:4:10)

Fix:

if (root) {