[448120] Adds FeatureMapChangeSpec with a useful toString() method

To ease debugging feature map changes, we introduce a new subclass
FeatureMapChangeSpec, corresponding to the already existing
ReferenceChangeSpec and AttributeChangeSpec, with a useful toString()
method providing all necessary information about a feature map change of
interest.

Bug: 448120
Change-Id: Ia24519c9e2d17c8180bbdf56ded03ab072e9730d
Signed-off-by: Philip Langer <planger@eclipsesource.com>
Parameterize project name and project id to ease reuse by other projects

Change-Id: Ib8afff7287c379049455b1d1bdc525005e6ebc41
Fix the labels of the SMV title bar

Instead of displaying "{0} over {1} differences still to be merged", it now 
display "{0} of {1} differences are not merged". It also updates the way the 
computation is done to be more accurate (no more truncating to 0 to avoid 
negative numbers...)

Change-Id: I0c6130e759866e820080807601de7ccd7634ff01