UIforETW with custom user-mode provider recording

This release of UIforETW allows arbitrary user-mode providers to be specified, so that the trace recording is now fully customizable.

The list of important changes is:

8c73a88 Add option to record extra user mode providers
e9caec6 Add checks for Python 2.7 to all scripts using subprocess
756b1cb Fix printing bug introduced during refactoring by ariccio
f9f56ea Increment version number to 1.32
fc74c20 Show version number in about box
de143e9 Hack IdentifyChromeProcesses.py to handle "missing" --type=

As usual the etwpackage.zip file contains 32-bit and 64-bit versions of UIforETW.exe, statically linked so that they will run anywhere. No compilation required. It also includes 64-bit versions of the Windows Performance Toolkit (WPT) installers.

To use this release just download and unzip etwpackage.zip and run bin\UIforETW. WPT 10 will be installed as needed.

Some anti-virus programs have occasionally flagged UIforETW*.exe as being malware. The cause of this flagging is not known but the flagging is assumed to be spurious. See #71 for a discussion of this issue.

For more information see https://tinyurl.com/etwcentral (aka https://randomascii.wordpress.com/2015/09/24/etw-central/)