Code refactor/restyle using clang-format

[redtide]

• Prettify the code following WebKit code style.
• Remove all wxT, unnecessary _() functions and wx version checks for old 2.9, support only 3.0+.
• Replace NULL with nullptr, make more use for modern c++.
• Minimize the use of helpers in TypeConv (eg. _STDSTR or _WXSTR)
• Check for conflicts with events from widgets designed at runtime and the application UI,
  probably caused by wrong IDs and/or static event tables.