Bugs fix

Fix inconsistent argument name in HTTP and Socks 5 single link.
Fix support for some non-standard ShadowsocksD subscription.
Fix include/exclude option in URL argument not overriding former settings.
Fix template system interpreting some comments in YAML files as line statement.
inja: re-implement variable accessing to catch exceptions on using not-exist variable and return an empty value.
Optimize codes.

base/base/all_base.tpl

@@ -6,13 +6,11 @@ allow-lan: {{ global.clash.allow_lan }}
 mode: Rule
 log-level: {{ global.clash.log_level }}
 external-controller: :9090
-{% if exists("request.clash.dns") %}
 {% if request.clash.dns == "1" %}
 dns:
   enabled: true
   listen: 1053
 {% endif %}
-{% endif %}
 {% if local.clash.new_field_name == "true" %}
 proxies: ~
 proxy-groups: ~