Ignore .dSYM folders
Introduce a CC make variable to use a custom gcc
Fix for printf errors, cast to an int to be sure
The OSX gcc compiler does not accept this option
Fix for gcc on OSX with missing struct initializers
Fix for zlib on OSX GCC
OSX gcc has no idea what this option is, so remove it for now.

It's been decided that we should move towards a private-by-default method and manually expose methods publically in the library. This patch will come seperately.
Correctly initialize variables
OSX fully supports these struct properties
Merge pull request #11 from duedil-ltd/fix/cleanup-compiler-errors

Fix compilation on Mac OSX 10.9.1 with Mac Clang
README, INSTALLING: Update per OS X fixes

Document CC option, add Tom (@tarnfeld) to contributors.