Merge pull request #31 from jamesmintram/master

fixed a llvm compiler issue - ambiguous call to abs
buildsystem: made search for pythoninterp, pythonlibs more resilient

fixes #26

we now search for pythonlibs, then for a pythoninterp that precisely matches the lib's version number.
Refactored the Opusfile cmake rules into own module

To properly find Opusfile on OS X (and possibly other systems too) a
hint had to be added to find the include directory of Opusfile. To keep
the CMakeLists.txt file clean, a new cmake module was created for
finding the Opusfile include directories and libraries.
Fix SDL2_image include directory hints for OS X systems
doc: added "troubleshooting" section to building.md
Include termios.h instead of the termio.h

Termio is specific for System III and System V machines and not part of
the POSIX standard (http://en.wikipedia.org/wiki/POSIX_terminal_interface#The_termios_data_structure).
buildsystem: prettified findopusfile
Merge branch 'master' of github.com:SFTtech/openage
Merge pull request #37 from svkurowski/fix_sdl2_image_hints

buildsystem: fix SDL2_image include directory hints for OS X systems
Merge pull request #39 from svkurowski/change_termio_include

util: include termios.h instead of the termio.h
Fixed a_start on Xcode 6.0