through environment vars

Set the log level with the environment variable "PYSCRIPT_LOG_LEVEL"
"DEBUG" (for debugging)
"ERROR" (show errors only)
"NONE"  (or anything else) (for production) is the default
and the log output type with the enviroment variable "PYSCRIPT_LOG_STDOUT"
"0" (log output to user/Scripts/python/log.txt)
"1" (or anything else) (log output to stdout)

Patch by: Tsutomu Uchino <hanya.runo@gmail.com>
Review by: Herbert Durr <hdu@apache.org>

Note: Commit message edited by ASF infra team to work around a known issue with the
ASF svn install (not an issue with svn) and UTF-8 handling. This is a temporary
issue that we hope to resolve soon.
(cherry picked from commit 9dc7f72f)

Change-Id: I099c8b3f812559c380078f63b692c83fdc811e33