Fixes #54 , #57

Changes

For Issue #54:

• Check if attribute exists, if so proceed
• If not, set the label to "None"
• Could issue a warning, but that would probably be ignored in this context and anyways there will be warnings issued from the idaes core code that builds the stream table earlier in the processing.

For Issue #57:

• Add 'strict' mode to validation, off by default
• Change failure for missing components in layout to warning in default (non-strict) mode

For general amusement:

• added some debug statements into the web server

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