Fixes "out-of-line definition" error in CLANG

```
> libspotify@0.0.1 install /Users/tim/Code/test/spotinfringe/lib/node-libspotify
> node-gyp configure build




  CXX(target) Release/obj.target/libspotify/src/album.o
In file included from ../src/album.cc:20:
../src/common.h:210:47: error: default arguments cannot be added to an out-of-line definition of a member
      of a class template
    ObjectHandle<T>::ObjectHandle(const char* name = NULL) : pointer(NULL) {
                                              ^      ~~~~
1 error generated.
make: *** [Release/obj.target/libspotify/src/album.o] Error 1
```
Fixes "no member named 'ca_certs_filename' in 'sp_session_config'"

```
../src/session.cc:310:10: error: no member named 'ca_certs_filename' in 'sp_session_config'
    ptr->ca_certs_filename              = NSP_STRING_KEY(obj, "ca_certs_filename");
    ~~~  ^
1 error generated.
make: *** [Release/obj.target/libspotify/src/session.o] Error 1
```
Merge branch 'osx-build-tcr'. close #1