Added pdh.go.
Added PdhValidatePathW.
Removed the W suffix from exported fields/funcs.

Copyright also changed to 2013 instead of 2010.
Specialized functions.

These specialized functions are necessary because of unions used in
structs in the C code.
Changed SzName to *uint16 accordingly.
Experimental stuff. Lots of nullptrs still.
Warning message for the LONG version.
Explanation of error code added.
MessageBeep added.
Added BUG description to the comment.
Added Kevin Pors to this file.
Sorted functions and type alphabetically.

Function signatures of the (...)Array functions now accept a pointer
to their respective structs, i.e. PDH_FMT_COUNTERVALUE_ITEM_DOUBLE.

The lpdwType parameter of the PdhGetFormattedCounterValue(...) is changed
to a *uint32 instead of the uintptr.

Adjusted examples in the function documentations.

Added a remark about PdhAddEnglishCounterW (which only resides on Windows
Vista and above - need to fix this with a version check in the future).
Merge pull request #2 from krpors/pdh-branch

Performance Counters branch (pdh.dll)