Resolve "SBML Reaction glyphs missing curve segment result in NullPointer exception"

Closes #647 (closed) Also SBML validation passes for multi package

added 8 commits

• dbe45fda - missing curve in reaction doesn't break import
• bd69ccf4 - extension of multi package to compartment added when necessary
• 53821d73 - reaction glyph always contain reaction line (sometimes only empty line)
• 538cc5ab - all feature tvalues have occurence set to 1
• 96ec0cfb - by default non existing boolean values in cell designer file are resovled to "false"
• 95701275 - default values for onstant and boundaryCondition provided
• a5a07982 - parameters are propagated only when not null
• 34ac408e - modification glyphs reference glyph is provided properly and bounding box is defined

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unmarked as a Work In Progress

changed the description

merged

mentioned in commit c2669340