* Update Scintilla to version 3.7.5

This now requires a C++11-capable compiler.

Closes #1308.

* Test using newer dist on Travis

Since Scintilla needs C++11

* Add debugging code for when configure fails

* Workaround a pkg-config-corsswrapper bug on Ubuntu 14.04

See https://bugs.launchpad.net/ubuntu/+source/mingw-w64/+bug/1327242