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Bugfixes:
- Fixed ``atexit`` handler.
This fixes issue 3.
- If a cache directory is specified, it will now be used even when not
in debug mode.
- Allow "comment" attribute in the TAL namespace.
This fixes an issue in the sense that the reference engine allows
any attribute within the TAL namespace. However, only "comment" is
in common use.
- The template constructor now accepts a flag ``debug`` which puts the
template *instance* into debug-mode regardless of the global
setting.
This fixes issue 1.
Features:
- Added exception handler for exceptions raised while evaluating an
expression.
This handler raises (or attempts to) a new exception of the type
``RenderError``, with an additional base class of the original
exception class. The string value of the exception is a formatted
error message which includes the expression that caused the
exception.
If we are unable to create the exception class, the original
exception is re-raised.