Basic functions for parsing commands added.

Basic functions for parsing commands added.

Added find_line_num function.  Counts line number error in pasring occured at.
This function may have issues with finding errors on first line.
Function has_more_commands has been inplemented.
Function advance can now rucursivly find next command in source file.
Function command_type determines which type each command is. Has extra
ability to look for commands that are not syntactically correct. Uses find_line
to report to user where error occurs first.
Function print_current_command has been created as a helper to display useful info
for debugging.
All of these changes need to be moved into another file.  When I find a suitable
method of doing this, I will make the change.