remove simplejson module, use (standart) json instead

since python 2.6+ simplejson is included in standard python lib as json module.

there are speed disputes: http://stackoverflow.com/a/16131316/78234
but measuring our usecase, .dumps() is used (slightly) more ofthen than .loads(), so json is faster.
Also, bug-fix support is better for json.
update files to import json instead of simplejson
tweepy installed by pip

before was only on Linux, now on both platforms
PS: why is this used? :)

Conflicts:
	external/common/requirements.txt
psutil installed by pip

version 1.0.1 used

Please test on MacOS, there were some .so files present there...?
remove unused Crypto module
YAML installed by pip

was external/linux64(darwin64)/lib/python2.6/site-packages/yaml
pip package is PyYAML
there's also a folder with C files: external/share/yaml-cpp