Fortran color code of END

The color for the single END in Fortran code was of the color of the flow type entities though for all the flow entities the entity name is mandatory. For the entity statements of some keywords e.g. SUBROUTINE and FUNCTION the entity name is not mandatory with the END statement. The color of the single END statement has been changed from the flow type to the normal keyword type.

Fix bug: language switch command skipped when langauge id contains "-" letter

Fixed typos in comments.

Support language switch for language ids, 'Japanese-en', 'Korean-en', 'Serbian-Cyrillic', and similer langauge ids.

Support visible=no for main page tab.

Bug ?? for page numbers in the latex indices

LaTeX problem with 2 consecutive single quotes

Due to the fact that the path was not stripped from the file name in case CREATE_SUBDIRS was set to YES there was a reference to a non existing page reference. In the corresponding hypertarget and label the path was already stripped.

In LaTeX 2 consecutive single quotes are joined to 1 double quote. This leads in texts where 2 single quotes are intended to a strange view. An example is the initial value for variables. E.g. in Fortran: character(len=10) :: A = ''  (i.e an empty string which can either be defined as '' or as "") or in C: char *sq  = "''". In the source listings this is OK but in the description text it was not OK.