Reduce syntactic diffs on ' = '

Changed behavior for template transclusion parameter serialization so that:
* ' = ' is used for new content
* ' = ' is used if the key part had a space before
* '=' is used otherwise.

This reduces the number of syntactic diffs a fair bit. On Obama for example,
the number of syntactic diffs drops from 94 to 65.

Change-Id: Ic6cfba86baf689a054234b176a98d7a6a1fa52db
Merge "Reduce syntactic diffs on ' = '"