[Tasks] Several tasks added.
[Code Clean] Removed unnecessary access identifier.

 * Also removed comment about tasks that won't necessary either.
[Aux] Using specialized exception instead of more generic while parsing configuration object.
[Breaking] Drop 'in situ' substitution mechanism for keyword attributes.

 * Without this mechanism it's possible to check formatter arguments in log macro in compile time using printf-like extension.
[Documentation] Added oxygen tag.
[API] The first argument is always string literal.
[Aux] Syntax checker is enabled again.
[Unit Testing] Suppress warning.

 * Because it's the test aim to check that there won't be any exception thrown if argument count is less than required.
[Aux] Format function doesn't throw anymore.
[Tasks] Remove some.

 * Format function doesn't throw anymore, so the first task is done by magic.
 * Looking for more performance gain from `boost::format` to something else.
[Documentation] Prettifying.
[Documentation] Synchronize.