Parser failures in cace_read

[RTimothyEdwards]

The cace_read parser fails to identify an illegal parameter name. Since parameter names are used to generate file names, they must be both unique and may not contain spaces.

The parser also fails to identify a spec entry, and possibly all key:value dictionary entries, in which a key is given but no value is given. In the case of a specification entry, such as "minimum:", a missing value should be set by default to "any". In other cases, defaults should be substituted as makes sense or else a missing value should flag an error.

Ideally, flagged errors should report a line number in the file.

Failure to read a file in cace-gui should not result in an exit, which causes error messages to disappear.