fix jshintrc issues + default .jshintrc

Ensure we use jshint default configuration by providing a dummy
.jshintrc

Fix issues in modules/ext.wikihiero.Special.js:

    line 32, col 17, Bad line breaking before '+'
    line 33, col 17, Bad line breaking before '+'
    line 34, col 17, Bad line breaking before '+'
    line 35, col 17, Bad line breaking before '+'

Change-Id: I06d91e6715c5ab00cacd4671507b8e7654e5ff18