Maintenance Sept.14

There is proposed a maintenance commit that targets improvements of

• formatting - usually corrects formatting after an acceptance of a compilation switch
• removal of empty lines
• addition/correction of comments
• "if defined XX" -> "ifdef XX" changes
• rename local "IVAS_PUBLIC_XX" constants to "XX"
• add keywords "const" and "static" where appropriate
• addition of missing error codes

It is noted that the changes focus on code parts that were changed recently and are related to CR fixes.