HwFileEventMgr: include <unistd.h>

This fixes the following compiles error (gcc 4.7.2):

HwFileEventMgr.cpp: In member function ‘virtual void lima::HwTmpfsBufferMgr::_CBK::prepare(const lima::DirectoryEvent::Parameters&)’:
HwFileEventMgr.cpp:122:21: error: ‘unlink’ was not declared in this scope
HwFileEventMgr.cpp: In member function ‘virtual bool lima::HwTmpfsBufferMgr::_CBK::newFrameReady(const HwFrameInfoType&)’:
HwFileEventMgr.cpp:145:24: error: ‘unlink’ was not declared in this scope
simutest: include <uinstd.h>

This fixes the following compile error (gcc 4.7.2):

simutest.cpp: In function ‘void simulator_test(double, long int)’:
simutest.cpp:73:19: error: ‘usleep’ was not declared in this scope
common/test: link with -lpthread

This fixes the following link error (gcc 4.7.2):

/usr/bin/ld: ../../build//liblimacore.so: undefined reference to symbol 'pthread_cancel@@GLIBC_2.2.5'
Merge pull request #7 from MaxIV-KitsControls/gcc-4.7

Fixes for gcc-4.7