Added possibility to invoke with multiple arguments

[DalderupMaurice]

Added variadic args for doInvoke and the proper parsing of each type of argument

Screenshot of invocation results as proof of work:

• 1 Invocation with a test smart contract (first 2 shown in screenshot are "normal" ones :P )
• 1 Invocation using CheckWitness with a test smart contract (The last one - parsing of address well done)
  

I am out after today until the end of the week
Things to do (I'll add these in as separate PR's as this is already a fully functioning piece)

• Ability to pass a variable length of arguments through invocations by apps
• Refactor @connect experimental annotations

[coveralls]

Coverage decreased (-0.3%) to 40.741% when pulling 997ec25 on DalderupMaurice:development into 33ee2db on CityOfZion:development.

[FredrikOseberg]

Please use buttons located in components/common/buttons. PrimaryButton and SecondaryButton components are made explicitly for NeoLink, and we are trying to move away from material library rmwc.

[DalderupMaurice]

Thanks, I'll update it!
Copied it from testInvoke - I'll include these too :)