Put the default settings in config.h.

Now the default settings are also put in the config.h so that it's easy to
print all default settings and keybindings to stdout. Added new option to dump
all default settings and keybindings to stdout (-D).

Parsing from default config is only a little slower than the previous
approach, but it more equal to the other configuration stuff.
Remove no more used global flag from settings.
Reduced the number of webkit settings.

The less setting we must parse the faster we can apply the settings. Also the
setting completions will keep readable. If anyone like a special setting to be
configurable to runtime, it's an easy job to add the item to the setting list
and to the default config.