Cleanup & strip unused methods

; Removed
: BBM.fn.pop()
: BBM.fn.push()
: BBM.uniq(array)
: BBM.unique(array)

; String type casting
: Use blank string concatenation instead of constructor.

; Unused constants
: Removed.

; Consolidate BBM.fn.toHTML(options)
: Make it easier to track the option object during traversal.

; Root node's URL symbol table.
: Changed its name to `node.symTable` from `node.refTable`