fix #315 improved test case

This improves the test case pushed in
5dc63fd637810862291ce5e31a6688dac4556487. Under some circumstances, the
old test may fail.
feat #327 improve error messages in assertEquals/NotEquals/JsonEquals

1. Allow usage of %1 %2 in assertEquals messages

%1 and %2 are shortcuts for value1 and value2 params passed to
%assertEquals and can be used as placeholders in the error message.

This commit implements the feature (Assert.js) and changes some of the
unit tests to use the new capability.

2. Fix the obvious issue with the error message of
'assertNotEquals'.

3. Write serialized versions of JSON entities in assertJsonEquals
in case there's no default error message passed.

Close #327. Close #328.
doc Update build info after changing commands in package.json
feat #339 PhantomJS Robot implementation