Misc hacks and stuff

The stuff in here is very low-fidelity

• u+.cc: Generate UTF-8 encoding of passed arguments:

    $ u+ 20ac
  

Generates the UTF-8 encoding of the euro symbol

• errno: print textual details of errno value

• aperf.cc: read MSR registers and aperf/mperf monitoring

• markov.cc: markov generator

• smbios.cc: peer into the SMBIOS on your computer