Rename --guess-parser option to --print-language

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Introduce --guess-language-eagerly(-G) option

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Use --guess-language-eagerly option when running tests

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
docs: describe --guess-language-eagerly(-G)

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Add a macro, ARRAY_SIZE for calculating the length of macro

Signed-off-by: Masatake YAMATO <yamato@redhat.com>