message: Update LINUX_HOWTO.txt
diff: -Please just type make in the main PCM directory and see what binaries have been build: ls *.x
  -
  -pcm.x - command line PCM utility
  -pcm-sensor.x - PCM plugin for use with KSysGuard
  -pcm-power.x - command line utility for reading energy and power related metrics on Intel(r) microarchitecture codename Sandy/Ivy-Bridge EP/EN/E/EX
  -pcm-memory.x - command line utility for reading memory channel related metrics on Intel(r) microarchitecture codename Sandy/Ivy-Bridge EP/EN/E/EX
  -pcm-msr.x - utility to read-write model specific registers
  -
  -if compiled with Linux perf (-DPCM_USE_PERF option in Makefile) then additionally CAP_SYS_ADMIN privileges needed for users executing the utilities
  -
  -
  +Refer to the main README ("Building PCM Tools" or "Downloading Pre-Compiled PCM Tools") sections
  