Added HTTP OPTIONS support:

     - added options to minilex.c
     - regenerated lextable.h
     - added WSI_TOKEN_OPTIONS_URI to libwebsockets.h
     - tweaked parsers.c to accommodate OPTIONS token
     - tweaked server.c to set uri_ptr and uri_len for HTTP callback on OPTIONS as well
Forgot to add WSI_TOKEN_OPTIONS_URI to the switch statement in parsers.
Added new HTTP headers and WSI tokens:

 - "access-control-request-headers:" <-- WSI_TOKEN_HTTP_AC_REQUEST_HEADERS
 - "if-none-match:" <-- WSI_TOKEN_HTTP_IF_NONE_MATCH
Merge branch 'feature/new_http_headers' into develop

Conflicts:
	lib/lextable.h