gitattributes and gitignore changes

Shell scripts that run on windows using cygwin should also have LF line
endings.
Visual Studio project DLL registration disabled

Disabled registration of DLLs after build (shows errors when VS is not
started as admin)
Option for silence on/off for text fragments

Silence at beginning and end of text fragments can now be set using a
Properties option defined in common.h
SAPI Bookmarks added

SAPI bookmarks are now supported (allows e.g. JAWS to continually read
word document)
Avoid hts_engine crash when empty labels array is provided (previously
there were always at least "sil" phones, with the new option to turn
them off, this might happen sometimes.