mktemp command is now invoked by means of the MKTEMP variable.
Corrected error when invoking the thot_ilm_perp program.
Added files related to cache n-gram language models.
Added -jm, -cjm and -i options.
HighSrc_to_Src() and HighTrg_to_Trg() functions redefined to implement
special treatment when string to WordIndex mapping is not found.
Added basic files to implement interpolated language models.