Updated editing support for tpl args with nowiki escaping in arg wt

* String fragments in edited params that might interfere with
  wikitext parsing are escaped.  Tokenizes the arg and tests string
  tokens for bad chars.

* TODO: Figure out a way to test this functionality.

* Tested with these and other combinations:

[subbu@earth tests] echo "{{echo | foo}}" | node parse | sed 's/foo/[[
[[ }} {{ bar }} | baz]]/g;' | node parse --html2wt --editMode
{{echo |<nowiki> [[ [[ }} </nowiki>{{ bar }}<nowiki> | baz]]</nowiki>}}

[subbu@earth tests] echo "{{echo | foo}}" | node parse | sed 's/foo/[[
[[ {{ bar }} | baz]]/g;' | node parse --html2wt --editMode
{{echo |<nowiki> [[ </nowiki>[[ {{ bar }} | baz]]}}

[subbu@earth tests] echo "{{echo | foo}}" | node parse | sed 's/foo/[[
{{ bar }} | baz]]/g;' | node parse --html2wt --editMode
{{echo | [[ {{ bar }} | baz]]}}

[subbu@earth tests] echo "{{echo|foo}}" | node parse | sed
's/"foo"/"
a}}"/g;' | node parse --html2wt --editMode
{{echo|<nowiki>
a}}</nowiki>}}

[subbu@earth tests] echo "{{echo|foo}}" | node parse | sed
's/"foo"/"{{a<\/s>"/g;' | node parse --html2wt --editMode
{{echo|<nowiki>{{a</nowiki>
}}

[subbu@earth tests] echo "{{echo|foo}}" | node parse | sed
's/"foo"/"{{a}}<\/s>"/g;' | node parse --html2wt --editMode
{{echo|{{a}}
}}

[subbu@earth tests] echo "{{echo|foo}}" | node parse | sed
's/"foo"/"
{{a}}"/g;' | node parse --html2wt --editMode
{{echo|<nowiki>
{{a}}</nowiki>}}

Change-Id: If1b9c7c1c22dd9a012b5afa48f37c0bc7fd0a165
Merge "Updated editing support for tpl args with nowiki escaping in arg wt"