Avoiding use of deprecated operator[]

The headers indicate using operator() instead which make sense from the source code as we are doing read-access and there's no need to expand the array if indices are greater than the current size.
Adapting all classes used in calls to despatchTypedData to use raw pointers instead.

Took the chance to also optimize a bit on a couple of spots by calling reserve on vectors which the resulting size was known.
Merge pull request #302 from ldmoser/fixBuild9

Fix build