Revert "hlp: Upgrade HLP to v20140312b"

This reverts commit c220348488bb9916a083dbe3b85f1a7a593be008.

There is a truncation bug in the new version making it unusable
despite it fixing #29.
hlp: Replace internal strncpy with memmove

strncpy has undefined behaviour when copying a string into
an overlapping buffer. Replace that call with a call to
memmove which explicitly handles this case.

Temporary fix for #29