[10414][fix] Missing const's in InstanceSave

[ciphercom]

There are no const declarations in the InstanceSave class. So no const variables of this type are possible. Added const keywords to functions that don't change the object.

Repository version was [s0132]

Author: me (github[at]ciphercom.de)

http://paste2.org/p/966591

[VladimirMangos]

In [10414]. Thank you

Sorry, forgot set author for commit