src/commands.c,src/commands.h: Refactor to provide new
get_token_no_blanks() function which is like get_token() but doesn't
skip blanks first.
src/datain.c: Remove superfluous call to skipblanks() before
get_token().
src/datain.c: Set pcs->infer for Compass DAT in terms of INFER_*
constants rather than to the literal 7.
src/datain.c: Move comments next to the code that they relate to.