Added additional include path to search within, supporting Mac OS brew u...

[tache]

This change resolves the issue where the include files for icu4c are not being found. They reside in the brew installed directory of /usr/local/include/unicode. The build was only searching in the /opt/local/include hierarchy common to MacPorts.

See these issues...
#47
#25

error experienced

> [email protected] install ./node_modules/node-stringprep
> node-gyp rebuild

  CXX(target) Release/obj.target/node_stringprep/node-stringprep.o
../node-stringprep.cc:2:10: fatal error: 'unicode/unistr.h' file not found
#include <unicode/unistr.h>
         ^
1 error generated.

[tache]

I should add that I ran into this when node-xmpp build failed. That module contains the node-xmpp-core dependency, which that build will still fail after this patch since the dependency in that module is

 'node-stringprep': '^0.4.0',

[lloydwatkin]

Thanks for your PR, am publishng now.

[lloydwatkin]

Pushed as 0.5.2

[lloydwatkin]

Also pushed [email protected] for this update.