Define the emphclass bits in liblouis.h in a better way.
Define the emphclass bits in liblouis.h in a better way.

The enum contains the official emph_ names.
The original constants (bold, italic, underline) are now #defines so
that code can test for their presence.
The comp_emph_1-3 #defines are based on the corresponding emph_
constants so that they can be independently removed or retained.

liblouis/liblouis,BueVest/liblouis,IndexBraille/liblouis,hammera/liblouis,vsmontalvao/liblouis,BueVest/liblouis,IndexBraille/liblouis,BueVest/liblouis,BueVest/liblouis,BueVest/liblouis,vsmontalvao/liblouis,hammera/liblouis,liblouis/liblouis,hammera/liblouis,vsmontalvao/liblouis,liblouis/liblouis,hammera/liblouis,hammera/liblouis,liblouis/liblouis,BueVest/liblouis,liblouis/liblouis,IndexBraille/liblouis,IndexBraille/liblouis,vsmontalvao/liblouis,vsmontalvao/liblouis,hammera/liblouis,IndexBraille/liblouis,liblouis/liblouis