Use check than return false when parsing the config files.

[alaxwang]

Hi:
Happy to propose a code change. The motivation to modified the config.h is from my own use case.
When I wrote a config file for adding a conv layer, I used a chinese charater '=' instead of ascii '=' by accident, which was really hard to notice.
So the run.sh give a weird error msg like "kernel size exceed input error", I spend a lots of time to figure out why the kernel size exceed. And I found the config was using a chinese charater '=', which cause the config parse skip the all configs content followed the invalid string.
I think generally the parser should check the invalid config file instead of just skip it. It's more clear for user, not like me spend a lot of time to debug the tool for reasoning unmatched error message.

[tqchen]

Thanks for the PR, I agree that a more robust config parser is indeed needed and helpful