Drop deprecated build options

These cause harm in connection with subprojects if the subprojects
yield to a deprecated option. So just rip the bandaid off and
drop the deprecated build options.

meson_options.txt

@@ -93,23 +93,11 @@ option('documentation',
        value: false,
        description : 'Build API reference and tools documentation')
 
-option('gtk_doc',
-       type: 'boolean',
-       value: false,
-       description : 'Build API reference and tools documentation',
-       deprecated: 'documentation')
-
 option('screenshots',
        type: 'boolean',
        value: false,
        description : 'Regenerate screenshots for the documentation')
 
-option('update_screenshots',
-       type: 'boolean',
-       value: false,
-       description : 'Regenerate screenshots for the documentation',
-       deprecated: 'screenshots')
-
 option('man-pages',
        type: 'boolean',
        value: false,
@@ -117,12 +105,6 @@ option('man-pages',
 
 # Demos, examples and tests
 
-option('demo-profile',
-       type: 'combo',
-       choices: [ 'auto', 'default', 'devel' ],
-       value: 'auto',
-       deprecated: 'profile')
-
 option('profile',
        type: 'combo',
        choices: [ 'auto', 'default', 'devel' ],
@@ -134,11 +116,6 @@ option('build-demos',
        value: true,
        description : 'Build demo programs')
 
-option('demos',
-       type: 'boolean',
-       value: true,
-       deprecated: 'build-demos')
-
 option('build-testsuite',
        type: 'boolean',
        value: true,