tagtree add %reload to allow hot reloading of tagnavi config

adds (static) function tagtree_unload
 frees all buflib allocations for tagtree

adds command %reload that allows a new tagnavi file to be loaded
without device restart
use it like so..
"Reload..." -> %reload

Allocations are now checked for validity (probably a good idea anyway)

Change-Id: I2b4b9b7e253f97f3e6575e0ea7a92905e004d47f
1 file changed