V0.12.1.x cleanup

[UdjinM6]

Rebased #548

• compiling warnings instantx.cpp:448:22: warning: variable ‘fFound’ set but not used  #541 masternodeman.cpp:806:14: warning: variable ‘isLocal’ set but not used #543 Warning: The name 'horizontalLayout_2_Main' (QHBoxLayout) is already in use, defaulting to 'horizontalLayout_2_Main1' #544
• masternode-budget: drop vchSig / fix constructors (inc. compiling error masternode-budget.cpp:1531:1: warning: base class ‘class CBudgetProposal’ should be explicitly initialized in the copy constructor #542 )
• output for txindex error
• CBitcoinAddress usage cleanup
• refresh qt project file
• fix typo in masternode debug category name (@crowning- was right about the need for some kind of dictionary 📖 there I guess)

EDIT: squashed everithing