build: Misc cleanup of options

Cleanup of option names, use features where applicable, and printing
of summary.

src/meson.build

@@ -1,13 +1,13 @@
 subdir('common')
 
-if get_option('with-gtk')
+if get_option('gtk-frontend')
   subdir('fe-gtk')
 endif
 
-if get_option('with-text')
+if get_option('text-frontend')
   subdir('fe-text')
 endif
 
-if get_option('with-theme-manager')
+if get_option('theme-manager')
   subdir('htm')
 endif