doxygen style for algorithm properties

[burlen]

The TECA_ALGORITHM_PROPERTY instantiations need to be converted to doxygen style. In the process run through a spell checker, fix capitalization, grammar, punctuation etc.

Here is an example:

    /** @anchor specific_humidity_variable
     * @name specific_humidity_variable
     * set the name of the variable that contains the specific humidity ("hus")
     */
    ///@{
    TECA_ALGORITHM_PROPERTY(std::string, specific_humidity_variable)
    ///@}

This was also discussed in #505