message: Cleaned up sort html doc
diff: @@ -59,13 +59,13 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  sort(const char *name, sort_spec dir); </font>
  </td>
  <td width = "33.3%">
  - Sort the DataFrame by the named column. If name equals "INDEX", it sorts by index. Otherwise it sorts by the named column. Sort first calls make_consistent() that may add nan values to data columns.<BR>
  + Sort the DataFrame by the named column. If name equals DF_INDEX_COL_NAME, it sorts by index. Otherwise it sorts by the named column. Sort first calls make_consistent() that may add nan values to data columns.<BR>
  nan values make sorting nondeterministic.
  </td>
  <td>
  <B>T</B>: Type of the by_name column. You always of the specify this type, even if it is being sorted to the default index<BR>
  <B>Ts</B>: The list of types for all columns. A type should be specified only once.<BR>
  - <B>name</B>: The name of a column or string "INDEX".<BR>
  + <B>name</B>: The name of a column or string DF_INDEX_COL_NAME.<BR>
  <B>dir</B>: Direction of sorting, ascending or descending
  </td>
  </tr>
  @@ -77,7 +77,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  sort(const char *name1, sort_spec dir1, const char *name2, sort_spec dir2); </font>
  </td>
  <td width = "33.3%">
  - This sort function sorts DataFrame based on two columns, also specified by the two directions. name[n] could be "INDEX" in whcih case the index column is taken as the sorting column.<BR>
  + This sort function sorts DataFrame based on two columns, also specified by the two directions. name[n] could be DF_INDEX_COL_NAME in whcih case the index column is taken as the sorting column.<BR>
  <B>NOTE</B>: The order of T[n] type specifications must match the order of name[n] column names. In addition, all column types must be specified separately. Otherwise, the behavior is undefined.<BR>
  <B>NOTE</B>: Sort first calls make_consistent() that may add nan values to data columns. nan values make sorting nondeterministic.
  </td>
  @@ -85,8 +85,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  <B>T1</b>: Type of the first named column. You always must specify this type, even if it is being sorted by the index.<BR>
  <B>T2</b>: Type of the second named column. You always must specify this type, even if it is being sorted by the index.<BR>
  <B>Ts</b>: List all the types of all data columns. A type should be specified in the list only once.<BR>
  - <B>name1</b>: Name of the first column or string "INDEX"<BR>
  - <B>name2</b>: Name of the second column or string "INDEX"<BR>
  + <B>name1</b>: Name of the first column or string DF_INDEX_COL_NAME<BR>
  + <B>name2</b>: Name of the second column or string DF_INDEX_COL_NAME<BR>
  <B>dir1</b>: Direction of sorting for the first column<BR>
  <B>dir2</b>: Direction of sorting for the second column
  </td>
  @@ -131,10 +131,6 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  </td>
  </tr>
  - <tr bgcolor="lightblue">
  - <th>Signature</th> <th>Description</th> <th>Parameters</th>
  - </tr>
  -
  <tr bgcolor="lightgrey">
  <td bgcolor="maroon"> <font color="white">
  template&lt;typename T, typename ... Ts&gt;<BR>
  