Mbed-flasher

This patch release just change return code to success when trying to erase platform (others than K64F) which is not yet implemented for flasher (only K64F is really supported).

Changes
84 return success code for erase even not supported target

The main new feature this release brings is the distinct exit codes based on daplink output on flash failures. This enables test automation to act accordingly.
Other additions include possibility to give custom logger as a parameter for Flash object and some test fixes.

All changes:
add a new public binary (74)
Exit code depending on fail reason (76)
Added ability to use custom loggers for Flash and Flasher objects. (73)
add tests for PR52 (72)
init idea for clean unneeded files (70)
fix unittest return failure (71)

Fix release to set correct mbed-ls versions for Windows and Linux.
Also adds Jenkinsfile.

All changes
use Jenkinsfile in CI (60)

Notes:
This release brings python3 support.
Flash and erase operations now wait (until timeout) for device to remount before returning.

All changes:
Verify mount point after erase (66)
add unittest support for py3 (63)
add unittest support for windows (64)
add an empty Jenkinsfile to trigger CI scan jobs (62)
read also lower-case mbed.htm (52)
Increase _verify_mount_point limit (58)
add run_pylint.sh and fix new warnings (59)
lint fix for `flashers` module (54)
Lint fix for other modules (55)
Py3 support (50)

Changes:
48 fix for missing logger when used from API
49 win10_fix_for_missing_drive