This commits fixes encoding issue using getWindowsCodePage
from Grass7Utils.py

All method in OtbUtils are decorated as static and is now in OtbUtils
class.

Instead of writing a cli_file at startup, provider now pass all
required env_variables in subprocess.popen.

Logging of output from otbalgorithm and updating progress bar is
slightly updated to work with all otb versions.
Algoirthm is launched directly using otbApplicationLauncherCommandLine
`encoding` (on windows) and env arguments passed to subprocess is
logged in QgsMessageLog

Add OTB_MAX_RAM_HINT and OTB_LOGGER_LEVEL issue #22. Other variables
seems not relevant to include in QGIS Processing provider settings

ram parameter is not added by default into all applications. It is now
controlled by config settings which btw ignore default value 128.

A "special" cli script is written to run otb application in all cases.
v0.1 uses custom script only for binary packages.

Config keys are moved a simply class OTBSettings which seems more
approriate for naming

This commit includes fixes fora half way refactoring of qgis processing
api which is going to remove WidgetWrapper class but not yet.

normpath used in last commit alone won't work for spaces in path.
We have to ensure_double_quotes for otbcli wrapper script used in
special cases. Currently this is broken on macos
otb#1745

This commit will put otb_cli_file inside double quotes. Tested on
OpenBSD using a path with spaces.
A unit-test has been added for future testing.

DOC: minor updates in the README

See merge request orfeotoolbox/qgis-otb-plugin!1

This reverts commit 8510098a.