libparnt: lock everything

+ there is a lock introduced in "Add global parser synchronous access mutex", but still draw3 segfaults on init
+ segfaults are not reproducible using valgrind, and happen in AddPar, where curr points to a badly initialized structure
+ altogether this looks very much like a multithreading issue
+ so introduce a recursive_lock, locking every single function in libparnt
+ this is extremely ugly, but it works and it doesn't slow down program start remarkably
+ a proper fix would be removing all the libparnt code and writing a new, simple, parser for szarp.cfg